You may often hear that fasting decreases hunger and improves fat loss. But is that really the case?
Overview
What did they test? The researchers systematically reviewed and meta-analyzed the literature to explore the effects of fasting on appetite and weight loss compared to a calorie deficit.
What did they find? There were no differences between intermittent fasting and a calorie deficit for either appetite or weight loss.
What does it mean for you? If you want to experiment with intermittent fasting to better manage your energy intake, feel free to do so. However, you should not expect to experience a greater decrease in appetite or weight loss than if you were to simply stick to a calorie deficit.
What’s the Problem?
Intermittent fasting was THE hottest thing in the fitness scene circa 2013, with multiple lifting personalities heavily promoting its fat loss and health benefits. For those who may be unaware, intermittent fasting involves cycling between controlled periods of food intake and unrestricted eating. Intermittent fasting manifests in different forms, including alternate-day fasting (ADF), 5:2 dieting, and time-restricted eating (TRE). Each variant introduces a distinctive rhythm to the eating-fasting cycle, contributing to the diversity of approaches within the intermittent fasting umbrella.
Despite intermittent fasting being presented as a revolutionary way to burn fat, manage appetite and increase muscle mass (via hormonal increases and other jargon), the current available literature has shown that many of its proposed benefits were highly overstated and it’s probably just another way for individuals to manage their energy intake. In a previous issue of REPS we looked specifically at whether training fasted or fed was better for muscle gains as well as whether the ingestion of carbohydrates after fasting for over 8 hours made any difference for lifting performance and saw that in both cases training fed led to better outcomes. Although intermittent fasting seems fine for muscle growth overall, the current evidence suggests that if you’re looking to maximize muscle gains, training fasted is probably not the best idea.
A critical aspect influencing the success of intermittent fasting is its alleged effect on appetite, the interplay of hunger, fullness, and the desire to eat. The dynamics of appetite become particularly relevant when considering adherence to intermittent fasting regimens with some suggesting that intermittent fasting might lead to increased hunger, potentially posing challenges to the fasting periods 1. Conversely, proponents argue that intermittent fasting could actually mitigate the typical increase in the 'drive to eat' associated with long-term continuous energy restriction 2.
But what does the entirety of the evidence suggest? Is Intermittent fasting the ultimate tool to suppress your appetite and better control your energy intake, or is an ol’ calorie deficit as good?
