Lack of compensation of energy intake explains the success of alternate day feeding to produce weight loss

Abstract

Background and AimsThis study was designed to obtain daily weighed food intake of participants engaged in Alternate Day Feeding (ADF). Prior ADF studies have used self-reported food intake, a method that has received criticism for its limited accuracy. Subjects and MethodsForty-nine university students received academic credit for participating in the study. Following a 10-day baseline period, participants underwent ADF for the next 8 days. Restricted daily intake to ∼ 75% of baseline food intake levels was followed by ad libitum intake on alternate days. Food intake was weighed before and after each meal. Daily body weight was also tracked. InterventionAfter the baseline period, participants underwent 8 days of ADF during which they consumed ∼ 75% of baseline energy intake by weight followed by ad libitum intake on alternate days. The trial concluded with 2 additional days of ad libitum feeding, for a total study duration of 10 days. ResultsDaily food intake was constant during the baseline period (slope = -0.93 g/d, p = 0.56), and did not differ significantly (995 g (95% CI [752, 1198]) from the total consumed on ad libitum ADF days (951 g (95% CI [777, 1227]). Intake on ad libitum days did not show a trend to increase during the intervention. Body weight declined significantly during ADF. ConclusionsADF produces significant weight loss because food intake does not increase on ad libitum feeding days to compensate for reduced intake on restricted energy days. Data are consistent with prior work that suggests humans do not fully compensate for imposed deficits in energy intake.