Intermittent Fasting and BMI: Understanding the Pros and Cons

A dietary pattern known as intermittent fasting (IF) alternates between periods of eating and fasting. The 16/8 approach, in which people fast for 16 hours and then eat within an 8-hour window, is one of the most well-known IF variations.

In recent years, IF has become more well-known as a weight loss method, and research indicates that it might be successful in this regard. According to one study, IF caused a 3-8% drop in body weight and a reduction in body fat percentage when compared to a control group (1). According to a different study, IF was just as successful at helping people lose weight as a standard calorie-restricted diet, but with better compliance and less muscle loss (2).

IF is not suitable for everyone, especially for those who are underweight or have a low body mass index, so it’s vital to keep that in mind (BMI).

A measurement of body fat based on height and weight is called BMI. BMIs between 18.5-24.9 are regarded as healthy, whereas BMIs under 18.5 are regarded as underweight. Due to the risk of nutrient deficits and further body weight loss for those with low BMIs, IF may not be recommended for them.

Additionally, it’s crucial for people with low BMIs to speak with a healthcare provider before beginning any diet or exercise program because they can have underlying medical issues that need to be taken into account.

Those who have specific medical issues, such as type 2 diabetes, or who are pregnant or nursing may not be able to use IF. It is usually advisable to seek medical advice before beginning a new eating regimen.

In conclusion, while IF may be a successful weight loss method for some people, it’s not suitable for everyone, especially those with a low BMI. Before beginning any new dietary regimen, it’s crucial to speak with a healthcare provider and to be aware of any underlying medical concerns.


  1. Heilbronn, L. K., Smith, S. R., Martin, C. K., Anton, S. D., & Ravussin, E. (2005). Alternate-day fasting in nonobese subjects: effects on body weight, body composition, and energy metabolism. The American Journal of Clinical Nutrition, 81(1), 69-73.
  2. Varady, K. A., Bhutani, S., Church, E. C., & Klempel, M. C. (2009). Short-term modified alternate-day fasting: a novel dietary strategy for weight loss and cardioprotection in obese adults. American Journal of Clinical Nutrition, 90(5), 1138-1143.

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