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Intermittent Fasting: Is It Really Effective for Weight Loss?

Mark Holland MD

Intermittent Fasting: Is It Really Effective for Weight Loss?

Evaluating the Effectiveness of Intermittent Fasting for Weight Loss: Investigate the benefits and drawbacks of intermittent fasting as a weight loss strategy. Learn about the various fasting protocols and their impact on metabolism, appetite regulation, and long-term weight maintenance.

Intermittent fasting (IF) has gained popularity as a weight loss strategy, but there are several arguments and evidence suggesting it may not be the most effective approach for everyone. In this article, we will discuss the potential drawbacks of IF and explore scientific evidence that challenges its efficacy for weight loss.

Ancestral Eating Patterns

Contrary to popular belief, our hunter-gatherer ancestors may not have experienced frequent periods of fasting. They likely ate whenever food was available, and periods of true fasting could have been rare. This suggests that intermittent fasting may not be a natural or optimal eating pattern for humans.

Postprandial Thermogenesis

Postprandial thermogenesis, or the energy expended in digestion and metabolism after a meal, can contribute to weight loss. Fasting for extended periods may disrupt this process, reducing the overall thermic effect of food and potentially hindering weight loss efforts.

Hunger and Adherence

Intermittent fasting can cause significant hunger, even during relatively short fasting periods. This can make it difficult for people to adhere to the fasting protocol, leading to lapses in compliance and, ultimately, reduced effectiveness for weight loss. Calorie-restrictive strategies often fail due to hunger, and intermittent fasting may face similar challenges.

Scientific Evidence Against Intermittent Fasting

Several studies have questioned the efficacy of intermittent fasting for weight loss. For instance:

  • A 2020 study published in JAMA Internal Medicine found no significant difference in weight loss between participants following a 16:8 intermittent fasting plan and those who ate three structured meals per day (1).

  • A 2017 review published in the American Journal of Clinical Nutrition concluded that intermittent fasting and continuous energy restriction resulted in similar weight loss and metabolic improvements (2).

These findings suggest that intermittent fasting may not offer significant advantages over other dietary strategies for weight loss.

In conclusion, intermittent fasting may not be the most effective weight loss strategy for everyone. Ancestral eating patterns, the potential disruption of postprandial thermogenesis, and the challenges of adhering to a fasting protocol due to hunger are all factors that can limit the success of intermittent fasting. Moreover, scientific evidence indicates that intermittent fasting may not provide substantial weight loss benefits compared to other dietary approaches. As such, individuals seeking to lose weight should consider a variety of strategies and consult with a healthcare professional to determine the most appropriate and sustainable method for their needs.


  1. Lowe DA, Wu N, Rohdin-Bibby L, et al. Effects of Time-Restricted Eating on Weight Loss and Other Metabolic Parameters in Women and Men With Overweight and Obesity: The TREAT Randomized Clinical Trial. JAMA Intern Med. 2020;180(11):1491-1499. doi:10.1001/jamainternmed.2020.4153

  2. Harris L, Hamilton S, Azevedo LB, et al. Intermittent fasting interventions for the treatment of overweight and obesity in adults aged 18 years and over: a systematic review and meta-analysis. Am J Clin Nutr. 2018 Feb 1;107(2):154-164. doi: 10.1093/ajcn/nqx028.


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