The Science Behind Intermittent Fasting (14 Studies) Nutritional Science Explained

This entry is part [part not set] of 48 in the series Science Explained Series by Jeff Nippard

Introduction

Intermittent fasting is a popular diet approach that claims to offer numerous health benefits, such as better fat loss, improved cardiovascular health, and better glucose control, all with less hunger and minimal risk of disordered eating or body image concerns. In scientific literature, it is usually referred to as alternate-day fasting or time-restricted feeding. This article will discuss the potential benefits, drawbacks, and effectiveness of intermittent fasting.

Intermittent Fasting: Benefits and Studies

Some of the benefits of fasting, mainly observed in rats, include:

  • Better weight loss
  • Improved cardiovascular health
  • Neuroprotective effects
  • Decreased cancer risk
  • Increased lifespan

These effects are independent of caloric restriction alone. One theory for these positive health effects is that periodic food deprivation serves as a preconditioning stress, enhancing resistance to more significant stresses in the future.

Human studies have also shown promising results, with two studies showing weight loss, reduced blood pressure, and lowered cholesterol in obese subjects following an alternate-day fasting diet for 8-10 weeks. However, two similar studies on lean individuals showed weight maintenance, indicating that alternate-day fasting may be a better weight loss strategy for obese individuals.

Hunger and Appetite

Contrary to concerns about increased hunger, studies have found that fasting can have an appetite-blunting effect. Maintaining a regular eating pattern can help control hunger with any diet, regardless of eating frequency.

Body Composition and Weight Loss

A systematic review of 40 studies found that intermittent fasting was better at suppressing hunger than continuous caloric restriction. However, this did not translate into significantly improved body composition or weight loss. The authors concluded that intermittent fasting is a valid, but not superior, option for weight loss compared to continuous energy restriction.

Muscle Mass and Metabolism

A common concern is that fasting can cause muscle loss. However, a 2006 paper showed that even 40 hours of fasting did not significantly alter negative regulators of muscle mass or cause significant muscle atrophy. Furthermore, fasting does not slow down metabolism, as changes in metabolic rate come from changes in daily caloric intake, not meal timing.

Considerations and Drawbacks

Optimizing Anabolism

A 2013 study found that consuming four 20-gram doses of whey protein was more effective in promoting anabolic signaling than consuming two doses of 40 grams or eight doses of 10 grams. This suggests that evenly spacing protein intake throughout the day across roughly four meals may be better for optimizing muscle growth.

Psychological Health and Adolescents

While some research has shown that intermittent fasting can reduce depression and binge eating, the Canadian Pediatric Society classifies fasting and skipping meals as unhealthy strategies for adolescents. Intermittent fasting may not be suitable for children and teenagers.

Conclusion

Intermittent fasting has proven to be an effective dieting methodology. However, it has not shown significant advantages over more standard diets that impose a caloric deficit with sufficient protein intake. For those who find it fitting for their preferences and lifestyle, intermittent fasting may be a viable option. Ultimately, the best diet is the one to which you can best adhere.

Series Navigation

You might like

© 2024 NETcortex - WordPress Theme by WPEnjoy