The Fasting and Shifted Timing (FAST) of Eating Study (FAST)

The aim of this study is to assess peoples' satisfaction with their diet based on adhering to three different meal-timing protocols for one week each: (1) Time-restricted feeding (TRF); (2) Intermittent fasting (IF); and (3) Alternate day fasting (ADF). The overall goal of this study is to determine if people would find it easy or difficult to follow these diet protocols for the purpose of weight management.

Fasting and time-restricted feeding (TRF) have become increasingly popular in nutrition research due to the potential health benefits they may provide. Several animal studies, and more recently some human studies, have indicated regular meal-timing (i.e. eating mostly in the day) or fasting have been beneficial for controlling weight, blood pressure, cholesterol, glucose, and insulin sensitivity. These types of eating patterns may offer the same "anti-aging" health benefits as traditional caloric restriction (i.e. consistent and routine adherence to a very low-calorie diet).While caloric restriction is considered the gold standard for weight management, weight regain often limits the long-term effectiveness of this approach. People often experience increases in hunger, which make it difficult to sustain this type of behavior.Therefore, researchers are turning to these dietary approaches as alternatives to low-calorie diets in an effort to obtain the same benefits, but with less burden on participants. However, it is not clear if the adherence to these types of diet protocols are any better than a low-calorie diet. Would people be more satisfied with meal-timing or fasting over a traditional very low-calorie diet? That is the main research question of this study.

Participants will eat the majority of their calories in the day. More specifically participants will consume 70% of their total calories before 5 pm and the remaining 30% after 5 pm.

This involves eating all of one's meals within a specific time (e.g. 8 hours) frame and fasting for the remaining hours (16 hours) in a day.

This involves complete fasting (i.e. no food or caloric containing beverages, only water consumption) for roughly an entire 36-hour period, followed by an ad libitum feeding day.

Inclusion Criteria: Be 18 years or older. Have a BMI between 25 - 49.9 kg/m2. Have a scale at home, or some way of weighing yourself regularly, so that you can report your body weight to the research staff. Be able to check emails regularly, because all of the surveys need to be completed online. Exclusion Criteria: NOT be already practicing any of these fasting approaches. NOT currently diagnosed with diabetes. NOT taking any appetite suppressants or prescription weight loss medications. NOT planning on getting pregnant within the next 6 weeks. Do NOT currently have any eating disorders. Have NOT lost or gained a significant amount of weight (i.e. 10 pounds or more) within the last 6 months.

Turner-McGrievy GM, Wirth MD, Bernhart JA, Aydin H. The Fasting and Shifted Timing (FAST) of Eating Study: A pilot feasibility randomized crossover intervention assessing the acceptability of three different fasting diet approaches. Appetite. 2022 Sep 1;176:106135. doi: 10.1016/j.appet.2022.106135. Epub 2022 Jun 16.