Does the Science Match the Hype on Intermittent Fasting?

Check out this answer from Consensus:

The current body of research supports the hype surrounding intermittent fasting to a significant extent. Intermittent fasting offers a promising non-pharmacological approach to weight loss and metabolic health improvement. However, more long-term studies are required to establish its efficacy and safety conclusively. For now, intermittent fasting can be considered a viable option for individuals looking to improve their metabolic health and manage weight.

Intermittent fasting (IF) has garnered significant attention as a potential strategy for weight loss and metabolic health improvement. But does the science support the hype? This article delves into the current research to evaluate the effectiveness and benefits of intermittent fasting.

What is Intermittent Fasting?

Intermittent fasting refers to eating patterns that cycle between periods of fasting and eating. Common methods include alternate-day fasting (ADF), time-restricted feeding (TRF), and periodic fasting (PF). These methods aim to reduce overall calorie intake and improve metabolic health by leveraging the body’s natural fasting state.

Weight Loss and Body Composition

Several studies have shown that intermittent fasting can lead to significant weight loss and improvements in body composition. For instance, a systematic review found that both ADF and TRF protocols positively affect weight control and biochemical parameters by regulating the circadian system and improving satiety control systems1. Another meta-analysis reported that intermittent fasting is associated with a significant decline in body mass index (BMI) and fasting glucose levels in the general population4.

Glycemic Control and Insulin Sensitivity

Intermittent fasting has also been studied for its effects on glycemic control and insulin sensitivity, particularly in individuals with type 2 diabetes mellitus (T2DM). A systematic review and meta-analysis found that intermittent fasting and continuous energy-restricted diets (CERD) had similar effects on glycemic control but that intermittent fasting had a better effect on weight loss2. Another study concluded that intermittent fasting is associated with greater weight loss in patients with T2DM compared to a standard diet, although it did not significantly impact HbA1c levels5.

Metabolic Health

The metabolic benefits of intermittent fasting extend beyond weight loss and glycemic control. Research indicates that intermittent fasting can improve lipid profiles, reduce blood pressure, and enhance overall metabolic health. For example, intermittent fasting has been linked to improvements in dyslipidemia and blood pressure, making it a viable option for individuals struggling with metabolic syndrome3. Additionally, intermittent fasting has been shown to remodel the intestinal microbiota, which plays a crucial role in metabolic health1.

Mechanisms of Action

The physiological mechanisms by which intermittent fasting exerts its benefits are multifaceted. These include the regulation of circadian biology, modulation of the gut microbiome, and activation of adaptive cellular stress response pathways. These mechanisms collectively contribute to improved mitochondrial health, DNA repair, and autophagy, which are essential for metabolic regulation and disease prevention8 10.

Safety and Long-term Effects

While the short-term benefits of intermittent fasting are well-documented, the long-term effects remain a subject of ongoing research. Current evidence suggests that intermittent fasting is a safe diet pattern for most individuals, including those with T2DM and metabolic syndrome2 6. However, more extensive and long-term studies are needed to fully understand its efficacy and safety over extended periods.

Does the science match the hype on Intermittent Fasting?

Krista Varady has answered Uncertain

An expert from University of Illinois at Chicago in Fasting, Kinesiology

Yes and No.

There are now several studies showing that intermittent fasting works for weight loss and heart disease/diabetes risk reduction. However, there are a lot of misconceptions on the underlying mechanisms.

It’s widely believed that intermittent fasting exerts these benefits through inducing autophagy. Autophagy means “self-eating” and is a process by which organisms get rid of damaged cell components by literally eating them. While there have been a few studies showing that fasting induces autophagy in yeast, this has never been shown in humans. It’s important to remember that, at present, there is no method available to measure autophagy in humans. So at this stage, we can’t say that the benefits of fasting seen in humans are because of autophagy.

Does the science match the hype on Intermittent Fasting?

Rebecca Reynolds has answered Unlikely

An expert from UNSW Sydney in Psychology

The hype on intermittent fasting seems to me to be greater than the science that backs it as one way to possibly improve aspects of longer-term health.

Does the science match the hype on Intermittent Fasting?

Michelle Harvie has answered Unlikely

An expert from Manchester University Hospital Foundation NHS Trust in Breast Cancer, Fasting, Dietetics

No we need more high quality research

Does the science match the hype on Intermittent Fasting?

Isabel Krug has answered Unlikely

An expert from University of Melbourne in Eating Disorders

There is science to intermittent fasting, although it is not as solid as its advocates would claim and findings are often inconsistent. Interestingly, even though dieting is one of the main risk factors for eating disorders and there is a lot of research on dieting in the eating disorder literature, there is surprisingly little research on the effects of different types of intermittent fasting on disordered eating.

Does the science match the hype on Intermittent Fasting?

Hiba Jebeile has answered Uncertain

An expert from University of Sydney in Nutrition

The science shows that various forms of intermittent fasting are as effective as continuous energy restriction or dieting every day. The science doesn’t suggest that it is any better on the whole. Some people may find intermittent fasting easier to follow and so it may have benefits for these people.