Intermittent fasting beneficial for weight loss: how is it that meal timing, regardless of calorie intake, can promote weight loss?
Diet trends continue to emerge and have phased in and out over the years from Atkins, Paleo to Ketogenic diet. These trendy diets seem to catch the attention of many people, including patients with diabetes. Clinicians constantly counsel patients with type 2 diabetes on the importance of a healthy lifestyle that oftentimes requires significant weight loss. Obesity is highly correlated with type 2 diabetes; therefore, patients with type 2 diabetes are often overwhelmed not only with a diabetes diagnosis, but with the task of weight loss. This is when patients are tempted to look for the latest fad diet for an easy fix. One of the most recent trending diet plans is intermittent fasting. Intermittent fasting consists of several different styles, including 16/8 method, where fasting occurs 16 hours per day, or the 5:2 intermittent fast, where fasting occurs for two whole days per week. Food is not allowed during fasting periods; only water, coffee, tea and other non-caloric beverages are permitted. Is intermittent fasting beneficial for patients with type 2 diabetes?
Many health benefits have been associated with intermittent fasting including weight loss, reductions in blood sugar and insulin levels, and significant increases in the Human Growth Hormone (HGH): during intermittent fasting, HGH has shown to increase as much as five times over. This hormone is produced by the pituitary gland, and increases glucose levels, and is therefore suppressed during feeding. Fasting is a great stimulus for secretion of HGH. Some studies even suggest that intermittent fasting may reduce risk for heart disease, Alzheimer’s disease and cancer. With the effects known on body weight, blood sugar and insulin levels, there is great interest in whether intermittent fasting may help to prevent or treat diabetes.
A recent study examined the effects of different schedules of intermittent fasting on appetite, metabolism, and fat burning. A small cohort of 11 adult men and women with overweight or obesity (BMI 25 – 35 mg/m2) practiced two different meal timing strategies in random order: a control schedule of three meals during a 12 hour period with breakfast at 8 AM and dinner at 8 PM, and an early time-restricted feeding (eTRF) schedule of three meals over a six hour period with breakfast at 8 AM and dinner at 2 PM. Each schedule provided the same amount and type of food as the other. On the fourth day of each diet, researchers measured the metabolism of participants in a respiratory chamber, which measures calories, carbohydrates, fat, and protein burned. Participants’ appetite levels were screened every 3 hours while awake, and their hunger hormone levels, ghrelin. Results showed that the eTRF schedule decreased levels of hunger hormone, ghrelin; decreased appetite; and increased fat-burning. This study had a significantly low population size, but provides some objective measurements regarding the metabolic effects from intermittent fasting.
Previous studies conflicted as to whether intermittent fasting weight loss was attributed to burning more calories or by lowering appetite. With the evidence from this recent study, it appears the effect is not on the amount of calories burned, but more on the increased overall efficiency of the metabolism. By limiting the time period during which one can eat, the amount of calories consumed intermittently will decrease in most people. Also, it is evident that a significant decrease in appetite occurs while practicing intermittent fasting. An observational study examined the effect of intermittent fasting for 24 hours for 2-3 days per week on diabetes. Three men with overweight, hypertension and hyperlipidemia were able to lose 10-18% of their body weight, reduce their fasting blood sugars and HbA1c, and discontinue most if not all diabetes medications. Although this study was only observational with only 3 patients, it is very significant to hear of patients eliminating diabetes medications from their treatment plan.
While diabetes patients are searching for a cure for obesity in order to maintain glycemic control, intermittent fasting may be a topic of discussion to address. It is important to discuss the risk of hypoglycemia during fasting periods. While educating patients on proper carbohydrate counting, intake of important nutrients, and proper exercise, intermittent fasting may be a good recommendation for patients with diabetes.
- Intermittent fasting is a diet which involves restricting caloric intake for periods of time such as 16/24 hours daily or for several days per week.
- Intermittent fasting has been shown to reduce appetite and hunger hormone, and increase fat burning to induce weight loss, which may be effective for patients with diabetes and obesity.
- Further research needs to be conducted to determine causation between intermittent fasting and glycemic control.
In this special interview, Dr. Mark Mattson discusses what resources are available for explaining the intermittent diet and how to get started. Dr. Mark Mattson is Chief of the Laboratory of Neurosciences at The National Institute on Aging Intramural Research Program at the NIH. He’s also a professor of neuroscience at Johns Hopkins University. Part 1
References for “Intermittent Fasting Beneficial for Weight Loss and Glycemic Control”:
“Meal-Timing Strategies Appear to Lower Appetite and Improve Fat Burning.” MDLinx, www.mdlinx.com/family-medicine/top-medical-news/article/2019/07/24/7573512?uic=ZZCE628C21DABE45DF95C1A9308F554865&utm_source=Sailthru&utm_medium=email&utm_campaign=Minor Morning July25&utm_term=Daily Update Minor Specialties With SailthruActivity.
“Planned Intermittent Fasting May Help Reverse Type 2 Diabetes, Suggest Doctors.” BMJ, www.bmj.com/company/newsroom/planned-intermittent-fasting-may-help-reverse-type-2-diabetes-suggest-doctors/.
Amber Satz, PharmD Candidate, LECOM School of Pharmacy