ABSTRACT

The aim of this study is to assess the effectiveness of intermittent fasting in improving and treating diabetes. Previous research asserts that diet plays an important role in diabetes management. With that, new research on different diets is currently arising to find the most effective diet in managing diabetes symptoms. 

To determine the effectiveness of intermittent fasting in relation to diabetes, a meta-analysis was conducted to analyze the results of 17 clinical trials. A total of 934 participants who were either obese, overweight, prediabetic, or type 2 diabetic were included in this study and four different methods of intermittent fasting were studied. 

It was concluded that 100% of the clinical trials showed improvement in diabetes parameters when the participants followed any form of intermittent fasting regimen. 

INTRODUCTION

Diabetes mellitus is an incurable chronic metabolic disease that comes in three forms: type 1 diabetes, type 2 diabetes, and gestational diabetes. Type 1 diabetes is characterized by the pancreas not being able to produce enough insulin (a hormone that regulates glucose in the blood), whereas type 2 diabetes is characterized by a decreased production of insulin over time and gradual insulin resistance (when cells don’t respond to insulin and increase blood sugar). Type 2 diabetes is the most common form of diabetes, accounting for 90-95% of all diabetes cases (What is diabetes?, 2023). The third type of diabetes, gestational diabetes is a form of diabetes in pregnant women characterized by high blood sugar (glucose in the blood) that typically goes away on its own after delivery. In total, diabetes affects 537 million adults worldwide and is responsible for 2.7 million deaths yearly (IDF diabetes atlas, 2021). By 2050, 1.31 billion people are projected to have diabetes (Global, regional, and national burden of diabetes from…, 2023). With the persistently rising numbers of diabetes cases each year, the need for a cure becomes increasingly urgent. 

While a cure for diabetes has been a topic of inquiry since the 1800s, a full cure has yet to be discovered. Different and varied approaches to treating diabetes are therefore still being piloted in an attempt to find a cure. Currently, the most common forms of treatment for diabetes include insulin injections as well as other insulin treatments. While these treatment options can help reduce the effects of diabetes, they are not permanent cures and require constant maintenance. Further, treating diabetes by injecting insulin into the body is not always effective and can lead to undesired outcomes such as hyperinsulinemia which requires increasing amounts of medication to overcome insulin resistance (Albosta et al., 2021). Additionally, diabetes treatment options such as insulin therapies are increasingly costly, rising by 35% over the last 10 years (New American Diabetes Association report…, 2023). Thus, though insulin injections and treatments are currently the standard medical response, there is room for other treatment options that may be more effective and have fewer undesired outcomes. One such option is to manage diabetes through a change in diet and lifestyle. It has been long established through a substantive body of research that a change in diet and lifestyle can help regulate blood sugar in all three types of diabetes. For example, one of the first steps recommended by doctors to newly diagnosed diabetes patients is to make changes in their lifestyle, specifically changes in diet and exercise patterns. Concurrent with these recommendations, research on diets and diabetes has significantly increased within the last few years. 

One limitation of treatments involving lifestyle changes is that they rely on the actions of the person with the condition. This finding is borne out in research across multiple medical concerns on how self-directed behavioral changes rely on the individual to take initiative and stick to the lifestyle change. The primary reason why lifestyle changes have not cured or significantly reduced the effects of diabetes is that it requires self-motivation and discipline. The effectiveness of different diets and lifestyle changes to improve diabetes has to be fully self-driven and cannot be forced, requiring meticulous calorie counting and strict dietary restrictions. Lifestyle changes are also not a permanent cure. Instead, they require a daily commitment to make changes in one’s diet and exercise as well as steady maintenance to improve regulatory factors and promote regression. At the end of the day, it is up to the patient to continue improving their health or fall back to their comforting habits. Despite the possible difficulties with treatments relying on lifestyle changes, many recent studies and clinical trials indicate that intermittent fasting may be a promising alternative to expensive diabetes treatments and a feasible option among the treatments that rely on lifestyle change.

Intermittent fasting is an eating regimen that requires no form of calorie restriction. Instead, it focuses on time-restricted eating in which a person has cycles of unrestricted eating and cycles of fasting. The most common forms of intermittent fasting include intermittent energy restriction, time-restricted fasting, and the alternate-day fasting method. Unlike more traditional diets, intermittent fasting does not primarily rely on calorie counting but instead focuses on counting time. Compared to other diets, intermittent fasting is much easier to adhere to. Counting time is notably easier than counting calories as noted by a participant survey from a clinical trial stating, “People in the fasting group reported that their diet was easier to adhere to than calorie restriction” (Pavlou et al., 2023). Additionally, with intermittent fasting, there is no necessary meal planning or preparation that typically follows different diets. Furthermore, there are no restrictions on what one is allowed to eat during the designated eating period, also called the feeding period. While still reducing the average calorie intake, intermittent fasting gives off the illusion of having the freedom to eat what one chooses without having to count the calories or feel guilty for having a sweet treat, eliminating the urge to “quit” when one has a sugar craving. This paper focuses on evaluating different intermittent fasting methods from various studies to compare data and conclude if intermittent fasting is an effective treatment option for people with diabetes. 

Gap in Research

While there are plenty of resources on intermittent fasting or diabetes alone, until recently, there has been relatively little pre-existing research on intermittent fasting in relation to diabetes management. Additionally, the physiological mechanisms underlying the benefits of intermittent fasting on diabetes remain relatively poorly understood. For example, it is not yet clear how intermittent fasting regimens can directly influence diabetes parameters such as insulin sensitivity, weight loss, and metabolic glucose, and if these results are simply due to chance. The purpose of this study is to address this gap and bring more awareness to the role of intermittent fasting as a lifestyle change that can help reduce the effects of diabetes and highlight areas where additional research would be helpful to more precisely determine the role of intermittent fasting in managing the effects of diabetes. 

LITERATURE REVIEW

The link between intermittent fasting and diabetes is a relatively new area with limited studies and human trials. Experiments conducted using various methods and subjects have revealed varying results that have nonetheless shown that the regulation of diabetic parameters correlates with fasting. Many diabetic individuals are recommended to follow weight management programs and follow low-calorie diets and caloric restriction plans. However, many new studies have revealed that intermittent fasting is an alternative diet that is easier to maintain and is more efficient in reducing the effects of diabetes.

Clinical Trials

Calorie restriction is one of the most popular ways to lose weight and works by reducing daily caloric intake. Due to its popularity, calorie restriction tends to rival intermittent fasting. However, clinical trials conducted by Pavlou et al. 2023, Harvie et al. 2010, Gabel et al. 2019, and many more have shown that intermittent fasting is more effective in improving diabetic parameters. The following three clinical trials have two independent groups featuring intermittent fasting and calorie restriction and a control group to compare the two interventions in relation to diabetes parameters. 

A clinical trial funded by the National Institute of Health compared fasting and calorie restriction in 75 obese, type 2 diabetic patients. Participants were randomly assigned into either a control group, intermittent fasting group, or calorie restriction group for six months. The intermittent fasting group followed the 16:8 fasting method and the calorie restriction group reduced their calorie intake by 25%. The control group did not change their diet at all. At the end of the six-month period, the fasting group had the most statistically significant results with the group losing an average of 3.6 percent of their body weight compared to the control group. The calorie restriction group did not lose a notable amount of weight but both the intermittent fasting group and calorie restriction group were able to healthily decrease blood glucose levels and reduce waist circumference without any side effects. Overall, the researchers concluded that intermittent fasting and time-restricted eating were more effective for weight loss and lowering blood glucose levels compared to calorie-restricted eating in obese adults with type 2 diabetes (Pavlou et al. 2023). 

Another trial that compared intermittent fasting and calorie restriction in 107 overweight women for six months revealed similar results. The intermittent fasting participants followed a 25% reduction intermittent energy restriction fasting method twice a week. The trial revealed that both intermittent fasting and calorie restriction are effective at blood pressure regulation and weight loss but intermittent fasting was more effective with an average weight loss of 14 pounds. The intermittent fasting group in this study also showed 3 key indicators: improvement in insulin sensitivity, reductions in fasting glucose, and insulin resistance (Harvie et al., 2010). In the results of the third trial, a 12-month trial that compared intermittent fasting (alternate-day method) and calorie restriction, alternate-day fasting produced a greater reduction in fasting glucose and insulin resistance compared to both the control and calorie restriction groups (Gabel et al., 2019). While intermittent fasting and calorie restriction are both common interventions that aim to reduce weight, all three clinical trials concluded that intermittent fasting is more effective than calorie restriction in relation to weight loss and regulating diabetes parameters. 

Below, research findings are summarized on the effect of intermittent fasting on three parameters of concern in managing diabetes: weight loss, glucose, and insulin.

Weight Loss

Numerous clinical studies (Arnason et al. 2017, Gabel et al. 2018, Pavlou et al. 2023, Sutton et al. 2018, Carter et al. 2018, Gabel et al., 2019, Sundfor et al. 2018, Carter et al. 2016, Harvie et al. 2013, Harvie et al. 2010, Keogh et al. 2014, Williams et al. 1998, Klempel et al. 2012, Kahleova et al. 2014,) have collectively shown a statistically significant decrease in weight when participants followed an intermittent fasting regimen. Weight management is one of the most important aspects of diabetes management. Weight gain with diabetes is particularly dangerous as it increases inflammation which further aggravates type 2 diabetes and disrupts the metabolism of glucose (Tsalamandris et al., 2019). Additionally, excess weight directly influences insulin sensitivity, insulin resistance, and blood glucose levels which all determine the severity of diabetes and can increase the risk of complications if they are not within safe parameters. Furthermore, diabetic individuals are much more susceptible to weight gain due to insulin irregularities. Sixty-two percent of adults with type 1 diabetes and 86 percent of adults with type 2 diabetes in the U.S. are considered to be obese or overweight (“Overweight and Obesity…”, 2023). Intermittent fasting has had very promising results in regulating weight loss in overweight and diabetic individuals.  

Glucose

There are many studies (Arnason et al. 2017, Cienfuegos et al. 2020, Sundfor et al. 2018, Harvie et al. 2013, Harvie et al. 2010, Hutchison et al. 2019, Klempel et al. 2012, Kahleova et al. 2014, and Pavlou et al. 2023) which have shown significant improvements in metabolic fasting glucose levels. Glucose is the body’s main source of energy and comes from breaking down food. One of the main indicators of diabetes is high blood glucose, however, having low blood glucose (also known as low blood sugar) levels is also a symptom of diabetes (“What Is Diabetes?”). Having high blood sugar or low blood sugar can cause common diabetes side effects such as shaking, sweating, anxiety, irritability, confusion, dizziness, fainting, hunger, blurred vision, nausea, fatigue, thirst, and dry mouth. With low blood glucose, the body produces ketones from stored fat to produce energy. If too many ketones are produced a condition called diabetic ketoacidoses can occur which is very serious and causes comas that can be potentially fatal (Manage Blood Sugar, 2022). Additionally, having high blood glucose causes hyperglycemia which can lead to long-term complications and puts an individual at increased risk for other diseases such as cardiovascular disease, neuropathy (nerve damage), diabetic nephropathy (kidney failure), and diabetic retinopathy (possible blindness) (Hyperglycemia, 2023). As seen by the long list of side effects, staying within the target range of blood glucose levels is imperative for diabetes management. Thus it is encouraging that intermittent fasting has had promising results in regulating glucose levels.  

Insulin

The clinical trials conducted by Gabel et al., 2019, Harvie et al. 2013, and Williams et al. 1998 have all shown significant improvement in the participants’ overall fasting insulin levels. For people without diabetes, insulin helps control blood sugar levels and store extra glucose for later use. However, for people with diabetes, the pancreas doesn’t produce enough insulin which causes high blood sugar (Diabetes Treatment, 2023). As explained in the previous paragraph, having high blood sugar as a diabetic can cause a variety of complications. One of the complications is high insulin resistance which makes it difficult for the body to take up insulin and contributes to high blood sugar. Intermittent fasting trials conducted by Cienfuegos et al. 2020, Gabel et al. 2019, Harvie et al. 2013, and Klempel et al. 2012 have all shown an improvement in insulin resistance in their fasting participants. Ideally, a person with diabetes would have low insulin resistance and high insulin receptivity. On the contrary, having low insulin resistance means having high insulin sensitivity which makes it easier for cells to respond to insulin and store glucose. Studies conducted by Sutton et al. 2018, Harvie et al. 2010, and Kahleova et al. 2014 have resulted in increased insulin sensitivity in their intermittent fasting participants. Both insulin resistance and insulin sensitivity influence an individual’s overall fasting insulin. Having proper fasting insulin levels helps regulate glucose and keep insulin levels at their optimal range to reduce the physiological effects of diabetes. Research outcomes showing a positive regulatory impact on the overall fasting insulin levels after intermittent fasting are promising. 

METHODOLOGY

In this study, I compared different trials of intermittent fasting to evaluate the effectiveness of different fasting methods. With the limitation of being an underage high school student, it was both unethical and unreasonable to conduct an experiment that included restricted eating patterns and human participants. To overcome this limitation, a comparative study including an in-depth meta-analysis was conducted to further investigate the effectiveness of intermittent fasting in reducing diabetes parameters. 

A mixed-method study was conducted to take advantage of the available quantitative data. The first approach used to formulate this meta-analysis included analytical research, fundamental research, and quantitative research using archival data. Utilizing different research methods allowed for a broader database to be utilized for a more limited and developing topic. A meta-analysis was chosen as the primary research method because it effectively utilized all the above research methods to compile data and compare clinical trials. Possible limitations that come with meta-analysis include the risk of bias when selecting studies as well as ignoring or not detecting differences in studies across an analysis.

Meta-analysis 

Table 1:Meta-analysis

Study
Participants
Design
Participants (I:C)
Age
Sex (F:M)
Duration (weeks)
Intervention
Control
Outcomes
Arnason et al. 2017
T2DM, Obese
Observational Study
10 (10:0)
53.8 ± 9.11
9:1
6
IF fast 18-20 h/day
NA
Weight, postprandial BG, FBG, BMI, SBP, WC
Carter et al. 2018
Type 2 Diabetes
Randomized Noninferiority
137 (70:67)
61±9
77:60
52
IER, 500-600 kcal/day
CER, 1200-1500 kcal/day
Weight, FM, BMI, HbAlc
Carter et al. 2016
Overweight/Obese
Parallel, Randomized,
63 (31:32)
61 ±8
33:30
12
IER: 400-600 kcal/day
CER: 1200-1500 kcal/day
Weight, FM, HbAlc
Cienfuegos et al. 2020 pt. A
Obese
Randomized Controlled
38 (19:19)
49±2
34:4
10
4-hour TRF: 3-7 pm
Usual diet pattern
FM, SBP, DBP, TG, LDL-C, HDL-C, FBG, Fins, HbAlc, HOMA-IR
Cienfuegos et al. 2020 pt. B
Obese
Randomized Controlled
39 (20:19)
46±3
36:3
10
6-hour TRF: 1-7 pm
Usual diet pattern
FM, SBP, DBP, TG, LDL-C, HDL-C, FBG, Fins, HbAlc, HOMA-IR
Gabel et al., 2019
Obese
Randomized Controlled
43 (11:17:15)
43
33:10
52
ADF 25% energy intake
Usual diet pattern
BMI, FM, Fins, IR
Gabel et al. 2018
Obese
Parallel Arm
46 (23:23)
50 ±2
41:5
12
8-hour TRF
Usual diet pattern
BP, Weight
Harvie et al. 2013
Overweight Women
Single-Centre Randomized
78 (38:40)
48.6±7.3
38:40
12
IECR and ad libitum
Daily energy restriction
Weight, WC, SBP, TC, LDL-C, HDL-C, FBG, Fins, HbAlc, HOMA-IR
Harvie et al. 2010
Obese Women
randomized parallel-arm
107 (1:1:1)
40.1
107:0
26
IER: 540 kcal/day  (2 days/week) 
CER: 1500 kcal/day for 7 days/week
Weight, IS, FBG
Hutchison et al. 2019
Overweight/Obese
Randomized Parallel-Arm
15 (15:0)
55 ±3
0:15
1
9-hour TRF (NA)
NA
GT, TG, glycemic response, FBG
Kahleova et al. 2014
T2DM
Randomized Crossover
54 (27:27)
59.4 ± 7
25:29
24
TRF 8-hours, 7 am-4 pm
CER: 500 kcal/day
Weight, HFC, FBG, glucagon, OGIS
Keogh et al. 2014
Overweight/Obese
Randomized Parallel-Arm
19 (10:9)
59.5 ±8.7
19:0
26
IER 1300 kcal for 1 week
CER
WC, hip circumference, weight
Klempel et al. 2013
Obese Women
Randomized Parallel-Arm
54 (54:0)
48 ± 2
54:0
10
IFCR-F, 30% restricted calorie
NA
Weight, FM, visceral fat, heart rate, FBG, IR, homocysteine
Pavlou et al. 2023
T2DM, Obese
Randomized Parallel-group
75 (1:1:1)
55
53:22
26
8-hour TRF
Usual diet pattern
Weight, FBG,WC, HbA1c, BMI,
Sundfor et al. 2018
Obese
Randomized Controlled
112 (54:58)
49.9±10.1
56:56
26
IER: 400/600 kcal/day
CER: reduced energy
Weight, WC, BMI, SBP, DBP, TC, TG, LDL-C, HDL-C, FBG, HbAlc
Sutton et al. 2018
Pre-Diabetic, Overweight men
Randomized Controlled
8 (8:0)
56±9
0:8
5
6-hour TRF last meal
12-hour feeding period
IS, BP, cell response, appetite, oxidative stress
Williams et al. 1998
Overweight, T2DM
Randomized Parallel-Arm
36 (18:18)
51.4±7.9
9:9
20
IER (5 days/week), 400-600 kcal/day
CER: 1,500-1,800 kcal/day every day
Weight, TC, TG, LDL-C, HDL-C, HbAlc, Fins
ADF= alternate day fasting; BMI = body mass index; C = control; CER = continuous energy restriction; DBP = diastolic blood pressure; FBG = fasting blood glucose; Fins = fasting insulin; FM = fat mass; GT= glucose tolerance; HbAlc = glycated hemoglobin; HDL-C = high-density lipoprotein cholesterol; HOMA-IR = Homeostatic Model Assessment for Insulin Resistance; I = intervention; IF= intermittent fasting; IECR = intermittent energy and carbohydrate restriction; IER = intermittent energy restriction; IR= insulin resistance; IS= insulin sensitivity; LCD = low-calorie diet; LDL-C = low-density lipoprotein cholesterol; OGIS= oral glucose insulin sensitivity; SBP = systolic blood pressure; TC = total cholesterol; TG = triglycerides; TRF = time-restricted fasting; T2DM= type 2 diabetes mellitus; WC = waist circumference.

To conduct this mixed method study, data was collected from various scientific journals including Pub Med, JSTOR, and Google Scholar. To avoid researcher bias, all studies related to intermittent fasting and diabetes were analyzed and compiled. Clinical trials and scientific studies were found through various databases using keywords such as “Diabetes and Intermittent Fasting”, “Effects of Fasting on Glucose”, “Diabetes Clinical Trials on Fasting”, and “Intermittent Fasting in Relation to Diabetes”. Date restrictions were placed between 2000-2024, and 229 results were available on JSTOR, 155 results were available on PubMed, and 19,500 results were available on Google Scholar. Studies that did not include complete texts did not relate to diabetes parameters, or focused on diets other than the different intermittent fasting methods were excluded from the study. After screening the studies using these previously mentioned parameters, 54 studies were evaluated. Additional studies were eliminated after reviewing the abstracts and screening titles. Thirty-three citations were further scrutinized to verify eligibility and a final of 19 studies were included in this study. Three out of the 19 final studies included multiple independent groups that compared additional diets such as caloric restriction to intermittent fasting and were ultimately excluded from the final meta-analysis due to relativity. A total of 934 patients were included in the final systematic review. A Google spreadsheet was then created to compare and contrast different clinical trials and their individual conclusions. 

All trials included in this comparative study were published between 1998 and 2024, with the majority of studies from 2018-2020. The sample sizes ranged from 8 to 137 participants and the duration of the interventions lasted from 1 week to 52 weeks, lasting on average 19.4 weeks. On average, 32% of the participants were male and 68% were female. The mean age of the participants was 52.1 years old, and in 15 out of 17 studies, the participants were overweight or obese. The different methods of intermittent fasting in the study included different time-restricted feeding (TRF), intermittent fasting with calorie restriction (IFCR), intermittent energy restriction (IER), alternate-day fasting (ADF), as well as other intermittent fasting methods. 

RESULTS

Table 2

Intervention
Outcomes
4-hour TRF
FM, SBP, DBP, TG, LDL-C, HDL-C, FBG, Fins, HbAlc, HOMA-IR
6-hour TRF
FM, SBP, DBP, TG, LDL-C, HDL-C, FBG, Fins, HbAlc, HOMA-IR
6-hour TRF 
IS, BP, cell response, appetite, oxidative stress
TRF 8-hours
Weight, HFC, FBG, glucagon, OGIS
8-hour TRF
Weight, DBG, WC, HbA1c, BMI,
8-hour TRF
BP, Weight
9-hour TRF 
GT, TG, glycemic response, FG
IER: 400-600 kcal/day
Weight, WC, BMI, SBP, DBP, TC, TG, LDL-C, HDL-C, FBG, HbAlc
IER: 400-600 kcal/day
Weight, FM, HbAlc
IER, 500-600 kcal/day
Weight, FM, BMI, HbAlc
IER: 400-600 kcal/day (5 days/week)
Weight, TC, TG, LDL-C, HDL-C, HbAlc, Fins
IER: 540 kcal/day (2 days/week) 
Weight loss, IS, FBG
IER 1300 kcal for 1 week
WC, hip circumference, weight
IECR and ad libitum
Weight, WC, SBP, TC, LDL-C, HDL-C, FBG, Fins, HbAlc, HOMA-IR
IFCR-F, 30% restricted calorie
Weight, FM, visceral fat, heart rate, FBG, Fins, homocysteine
IF fast 18-20 h/day
Weight, postprandial BG, FBG, BMI, BP, WC
ADF 25% energy intake
BMI, FM, Fins, IR

ADF= alternate day fasting; BMI = body mass index; C = control; CER = continuous energy restriction; DBP = diastolic blood pressure; FBG = fasting blood glucose; Fins = fasting insulin; FM = fat mass; GT= glucose tolerance; HbAlc = glycated hemoglobin; HDL-C = high-density lipoprotein cholesterol; HOMA-IR = Homeostatic Model Assessment for Insulin Resistance; I = intervention; IF= intermittent fasting; IECR = intermittent energy and carbohydrate restriction; IER = intermittent energy restriction; IR= insulin resistance; IS= insulin sensitivity; LCD = low-calorie diet; LDL-C = low-density lipoprotein cholesterol; OGIS= oral glucose insulin sensitivity; SBP = systolic blood pressure; TC = total cholesterol; TG = triglycerides; TRF = time-restricted fasting; T2DM= type 2 diabetes mellitus; WC = waist circumference.

All evaluated studies revealed a significant improvement in multiple diabetic parameters. The parameters and the number of studies with each finding are summarized here: lower fat mass (6), improved systolic and diastolic blood functions (4), improved triglycerides (5), decreased low-density lipoprotein cholesterol and increased high-density lipoprotein cholesterol (5), improved fasting glucose (7), improved fasting insulin (6), weight loss (12), improvement in glycated hemoglobin levels (7), decrease in body mass index (5), and reduced waist circumference (5). As seen in Table 2 above, the most common outcomes across all the intermittent fasting interventions were weight loss, improved fasting blood glucose, and improved glycated hemoglobin levels. The least common results included improved oxidative stress, homocysteine, heart rate, and visceral fat. Additionally, fasting methods with some sort of calorie regulation such as intermittent energy restriction (uses intermittent fasting through periods of caloric deficit and maintenance) had stronger results in weight loss. Intermittent energy restriction had stronger results in weight loss compared to time-restricted fasting. Nonetheless, all evaluated clinical trials showed tremendous success in improving different aspects of diabetes. Each form of intermittent fasting intervention improved multiple diabetes parameters increasing the potential to promote regression and avoid medication. Intermittent fasting is a promising alternative to daily diabetes medication and insulin therapies. 

DISCUSSION

While all methods of intermittent fasting showed notable improvement in diabetic parameters, the type of method used should be carefully considered by each individual. In all of the studies there were no severe side effects but fasting methods with 6 hours or less of feeding periods were more prone to minor side effects. These side effects included dizziness, fatigue, nausea, gastrointestinal issues, and headache (Cienfuegos et al., 2020). And though it may seem as if longer fasts result in greater weight loss, further scrutiny of individual participant results from a clinical trial conducted by Cienfuegos revealed that longer fasting methods were not related to weight loss. In fact, the 18-hour fast group ended up losing much more lean mass than the 20-hour fast group (Cienfuegos et al., 2020). Furthermore, intermittent fasting methods with prolonged fasting in underweight individuals can potentially be dangerous and have serious consequences such as organ damage. Other intermittent fasting studies on non-diabetic and normal-weight participants have revealed increased insulin resistance and hypoglycemia (Arnason et al., 2017). This, however, may only be because most intermittent fasting trials on diabetes have only tested individuals with type 2 diabetes, including all evaluated studies above, because type 1 diabetes is at increased risk for hyperglycemia complications. Diabetes affects everyone differently, so it is highly recommended to talk with a doctor to decide if intermittent fasting is a safe option and to discuss the specific method and intervention. 

Filling the Gap

This research paper helps highlights some of the gaps from the preexisting research on this topic. While prior studies did not mix subjects of different health backgrounds, this study included a more diverse subject pool with non-diabetic, overweight individuals, pre-diabetic individuals, and type 2 diabetic individuals all participating in this study. This allows for a larger database that can be used to determine if the results of this meta-analysis can be applied to only one group of people or a larger array of people. The largest gap filled was compiling the limited clinical trials on the effect of intermittent fasting in diabetes to show and conclude the direct influence intermittent fasting has on diabetes parameters. All studies and researchers strongly agreed that lifestyle changes including diet play a huge role in the maintenance of diabetes. They also concluded that fasting directly affects diabetic parameters. However, the effectiveness and risk factors of intermittent fasting on diabetes still remain a topic of dispute and warrant further study. 

Implications

The results of this study show promising results in reducing the effects of diabetes by following an intermittent fasting regimen. This is important because studies have been showing that following the intermittent fasting regimen can improve health by preventing further progression of diabetes and can even balance out glucose levels which can eliminate the need for constant medication and insulin treatments. Individuals who are overweight, pre-diabetic, or diagnosed with type 2 diabetes, and were unaware of the benefits of intermittent fasting on their condition may be introduced to this new lifestyle plan that can better their health. Both preexisting and current research imply that the prevalence of diabetes is continuing to scale upwards. With the help of this study and many more to come, diabetic individuals can find alternative ways to treat diabetes. The hope is that as the effectiveness of treatment modalities such as intermittent fasting are researched and understood, the findings will illuminate the path to not only managing diabetes but also finding a cure. 

Limitations

There is one obvious limitation: the author is an underage high school student without the authority to conduct a human participant clinical trial. In addition, there was also limited access to resources. Many clinical trials that initially had been chosen to be included in the meta-analysis were omitted due to the restrictive free access to the article. Another limitation of this study is the fact that all the clinical trials measured different outcomes. The measurement of different outcomes skews the data and strictly alters the mode of different diabetes parameters. This is because there were multiple different independent variables such as the type of intermittent fasting regimen, duration of the study, and length of daily feeding and fasting periods. With the measurement of different specific outcomes per clinical trial, it is more difficult to decipher if a specific intermittent fasting regimen is more successful in reducing a specific diabetes parameter compared to other fasting regimens. Additionally, with so many different outcomes, it is harder to confirm if that specific outcome is due to chance or statistically significant in trials with the same independent variables. Addressing the limitations of this study and addressing the differences in each clinical trial will produce a more accurate and valid study.

Future Direction

Due to the fact that this specific topic is relatively new and understudied, there is still much room for more in-depth and new areas of research. This study provides a database compiling many of the available resources on this topic that can be used to further scrutinize the effectiveness of intermittent fasting in relation to diabetes. Further research on the specific method of intermittent fasting can attempt to determine if one method is more effective than the other in managing diabetic parameters. Additionally, the subject pool can be expanded to discover if the findings of this study can be applied to the general population or remain specific to a group. Expanding the subject pool to different diseases may also catalyze new areas of research. Within the field of diabetes, there is so much that can be learned and much more that can be discovered as technology continues to advance and new discoveries are made. 

REFERENCES

Albosta, M., Bakke, J. (2021, February 3). Intermittent fasting: is there a role in the treatment of diabetes? A review of the literature and guide for primary care physicians. Clin Diabetes Endocrinol 7, 3 doi.org/10.1186/s40842-020-00116-1

Arnason, T. G., Bowen, M. W., & Mansell, K. D. (2017). Effects of intermittent fasting on health markers in those with type 2 diabetes: A pilot study. World journal of diabetes, 8(4), 154–164. doi.org/10.4239/wjd.v8.i4.154

Carter, S., Clifton, P. M., & Keogh, J. B. (2018). Effect of Intermittent Compared With Continuous Energy Restricted Diet on Glycemic Control in Patients With Type 2 Diabetes: A Randomized Noninferiority Trial. JAMA network open, 1(3), e180756. doi.org/10.1001/jamanetworkopen.2018.0756

Carter, S., Clifton, P. M., & Keogh, J. B. (2016). The effects of intermittent compared to continuous energy restriction on glycaemic control in type 2 diabetes; a pragmatic pilot trial. Diabetes research and clinical practice, 122, 106–112. doi.org/10.1016/j.diabres.2016.10.010

Cienfuegos, S., Gabel, K., Kalam, F., Ezpeleta, M., Wiseman, E., Pavlou, V., Lin, S., Oliveira, M. L., & Varady, K. A. (2020). Effects of 4- and 6-h Time-Restricted Feeding on Weight and Cardiometabolic Health: A Randomized Controlled Trial in Adults with Obesity. Cell metabolism, 32(3), 366–378.e3. doi.org/10.1016/j.cmet.2020.06.018

Diabetes treatment: Using insulin to manage blood sugar. (2023, August 4). Mayo Foundation for Medical Education and Research. Mayo Clinic. mayoclinic.org/diseases-conditions/diabetes/in-depth/diabetes-treatment/art-20044084 

Diet review: Intermittent fasting for weight loss. (2022, May 17). The Nutrition Source. hsph.harvard.edu/nutritionsource/healthy-weight/diet-reviews/intermittent-fasting/#:~:text=Intermittent%20fasting%20is%20a%20diet,and%20periods%20of%20unrestricted%20eating 

Gabel, K., Hoddy, K. K., Haggerty, N., Song, J., Kroeger, C. M., Trepanowski, J. F., Panda, S., & Varady, K. A. (2018). Effects of 8-hour time restricted feeding on body weight and metabolic disease risk factors in obese adults: A pilot study. Nutrition and healthy aging, 4(4), 345–353. doi.org/10.3233/NHA-170036

Gabel, K., Kroeger, C. M., Trepanowski, J. F., Hoddy, K. K., Cienfuegos, S., Kalam, F., & Varady, K. A. (2019). Differential Effects of Alternate-Day Fasting Versus Daily Calorie Restriction on Insulin Resistance. Obesity (Silver Spring, Md.), 27(9), 1443–1450. doi.org/10.1002/oby.22564

Global, regional, and national burden of diabetes from … (2023, June 22). Elsevier Ltd. The Lancet. thelancet.com/journals/lancet/article/PIIS0140-6736(23)01301-6/fulltext 

Harvie, M. N., Pegington, M., Mattson, M. P., Frystyk, J., Dillon, B., Evans, G., Cuzick, J., Jebb, S. A., Martin, B., Cutler, R. G., Son, T. G., Maudsley, S., Carlson, O. D., Egan, J. M., Flyvbjerg, A., & Howell, A. (2010). The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women. International journal of obesity (2005), 35(5), 714–727. doi.org/10.1038/ijo.2010.171

Harvie, M., Wright, C., Pegington, M., McMullan, D., Mitchell, E., Martin, B., Cutler, R. G., Evans, G., Whiteside, S., Maudsley, S., Camandola, S., Wang, R., Carlson, O. D., Egan, J. M., Mattson, M. P., & Howell, A. (2013). The effect of intermittent energy and carbohydrate restriction v. daily energy restriction on weight loss and metabolic disease risk markers in overweight women. The British journal of nutrition, 110(8), 1534–1547. doi.org/10.1017/S0007114513000792

Hutchison, A. T., Regmi, P., Manoogian, E. N. C., Fleischer, J. G., Wittert, G. A., Panda, S., & Heilbronn, L. K. (2019). Time-Restricted Feeding Improves Glucose Tolerance in Men at Risk for Type 2 Diabetes: A Randomized Crossover Trial. Obesity (Silver Spring, Md.), 27(5), 724–732. doi.org/10.1002/oby.22449

Hyperglycemia: Symptoms, causes, and treatments. (2023, November 1). Yale Medicine. yalemedicine.org/conditions/hyperglycemia-symptoms-causes-treatments#:~:text=In%20general%2C%20hyperglycemia%20that%20is,nerve%20damage%2C%20and%20cardiovascular%20disease 

IDF diabetes atlas. (2021). International Diabetes Federation. diabetesatlas.org/#:~:text=Diabetes%20around%20the%20world%20in%202021%3A,%2D%20and%20middle%2Dincome%20countries.  

Kahleova, Hana, et al. “Eating two larger meals a day (breakfast and lunch) is more effective than six smaller meals in a reduced-energy regimen for patients with type 2 diabetes: a randomized crossover study.” Diabetologia vol. 57,8 (2014): 1552-60. doi:10.1007/s00125-014-3253-5

Karamanou, M., Protogerou, A., Tsoucalas, G., Androutsos, G., & Poulakou-Rebelakou, E. (2016). Milestones in the history of diabetes mellitus: The main contributors. World journal of diabetes, 7(1), 1–7. doi.org/10.4239/wjd.v7.i1.1

Keogh, J. B., Pedersen, E., Petersen, K. S., & Clifton, P. M. (2014). Effects of intermittent compared to continuous energy restriction on short-term weight loss and long-term weight loss maintenance. Clinical obesity, 4(3), 150–156. doi.org/10.1111/cob.12052

Klempel, M. C., Kroeger, C. M., & Varady, K. A. (2013). Alternate-day fasting increases LDL particle size independently of dietary fat content in obese humans. European journal of clinical nutrition, 67(7), 783–785. doi.org/10.1038/ejcn.2013.83

Manage blood sugar. (2022, September 30). Centers for Disease Control and Prevention. cdc.gov/diabetes/managing/manage-blood-sugar.html#:~:text=It’s%20important%20to%20keep%20your,improve%20your%20energy%20and%20mood. 

New American Diabetes Association report finds annual costs of diabetes to be $412.9 billion. (2023, November 1). American Diabetes Association. diabetes.org/newsroom/press-releases/new-american-diabetes-association-report-finds-annual-costs-diabetes-be

“Overweight and Obesity in People with Type 1 Diabetes Nearly Same as General Population.” (2023, February 13). Johns Hopkins Bloomberg School of Public Health. publichealth.jhu.edu/2023/overweight-and-obesity-in-people-with-type-1-diabetes-nearly-same-as-general-population#:~:text=The%20researchers%20found%20that%2062,adults%20with%20type%202%20diabetes. 

Pavlou, V., Cienfuegos, S., Lin, S., Ezpeleta, M., Ready, K., Corapi, S., Wu, J., Lopez, J., Gabel, K., Tussing-Humphreys, L., Oddo, V. M., Alexandria, S. J., Sanchez, J., Unterman, T., Chow, L. S., Vidmar, A. P., & Varady, K. A. (2023). Effect of Time-Restricted Eating on Weight Loss in Adults With Type 2 Diabetes: A Randomized Clinical Trial. JAMA network open, 6(10), e2339337. doi.org/10.1001/jamanetworkopen.2023.39337

Richter, Amy, Cecilia Snyder, Kris Gunnars. (2023, June 2). 5 intermittent fasting methods, reviewed. Healthline. Healthline Media. healthline.com/nutrition/6-ways-to-do-intermittent-fasting#what-it-is 

Robert R Henry, Barry Gumbiner, Timothy Ditzler, Penny Wallace, Rachel Lyon, Harry S Glauber. (1993, January 1). Intensive Conventional Insulin Therapy for Type II Diabetes: Metabolic effects during a 6-mo outpatient trial. Diabetes Care. 16 (1): 21–31. doi.org/10.2337/diacare.16.1.21\

Sundfor, T. M., Svendsen, M., & Tonstad, S. (2018). Effect of intermittent versus continuous energy restriction on weight loss, maintenance and cardiometabolic risk: A randomized 1-year trial. Nutrition, metabolism, and cardiovascular diseases : NMCD, 28(7), 698–706. doi.org/10.1016/j.numecd.2018.03.009

Sutton, E. F., Beyl, R., Early, K. S., Cefalu, W. T., Ravussin, E., & Peterson, C. M. (2018). Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes. Cell metabolism, 27(6), 1212–1221.e3.

Tsalamandris, S., Antonopoulos, A. S., Oikonomou, E., Papamikroulis, G.-A., Vogiatzi, G., Papaioannou, S., Deftereos, S., & Tousoulis, D. (2019, April). The role of inflammation in diabetes: Current concepts and future perspectives. European cardiology. ncbi.nlm.nih.gov/pmc/articles/PMC6523054/ 

What is diabetes? (2023, September 5). Centers for Disease Control and Prevention. cdc.gov/diabetes/basics/diabetes.html

“What Is Diabetes?” (2023, April). National Institute of Diabetes and Digestive and Kidney Diseases, U.S. Department of Health and Human Services, www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes#:~:text=Diabetes%20is%20a%20disease%20that,to%20be%20used%20for%20energy.

Williams, K. V., Mullen, M. L., Kelley, D. E., & Wing, R. R. (1998). The effect of short periods of caloric restriction on weight loss and glycemic control in type 2 diabetes. Diabetes care, 21(1), 2–8. doi.org/10.2337/diacare.21.1.2

Yuan, X., Wang, J., Yang, S., Gao, M., Cao, L., Li, X., Hong, D., Tian, S., & Sun, C. (2022). Effect of Intermittent Fasting Diet on Glucose and Lipid Metabolism and Insulin Resistance in Patients with Impaired Glucose and Lipid Metabolism: A Systematic Review and Meta-Analysis. International Journal of Endocrinology, 2022, 1–9. doi.org/10.1155/2022/6999907