Alternate day fasting verse reduced calorie restriction

An article recently published in JAMA studied alternate day fasting.

The question was,

“Is alternate-day fasting more effective for weight loss and weight maintenance compared with daily calorie restriction?”

The results of the study did not show a significant difference between people who were on a calorie restricted diet or those who followed an alternate day fasting diet.

Their study concluded, “Alternate-day fasting did not produce superior adherence, weight loss, weight maintenance, or cardioprotection vs daily calorie restriction.”

What is the definition of an alternate fast day?

In this study people who were on an alternate day fasting consumed 25% of their usual intake which was approximately 500 kcal. This was alternated with a feast day where individuals were permitted to consume food without restriction.

Up until now, there have been no long-term randomized clinical trials that have evaluated alternate fast day efficacy.

Alternate day fasting findings

It was difficult to maintain a fast on alternate days.

It was interesting to note that the highest dropout rate was in the alternate day fasters.

“Participants in the alternate-day fasting group ate more than prescribed on fast days, and less than prescribed on feast days, while those in the daily calorie restriction group generally met their prescribed energy goals.”

There were no significant differences between the intervention groups in blood pressure, heart rate, triglycerides, fasting glucose, fasting insulin, insulin resistance, C-reactive protein, or homocysteine concentrations at month 6 or 12.

Mean low-density lipoprotein cholesterol levels were significantly elevated by month 12 among the participants in the alternate-day fasting group compared with those in the daily calorie restriction group. Blood levels of low-density lipoprotein cholesterol (LDL-C) are often assessed when evaluating the risk of future heart disease.


Trepanowski JF, Kroeger CM, Barnosky A, Klempel MC, Bhutani S, Hoddy KK, Gabel K, Freels S, Rigdon J, Rood J, Ravussin E, Varady KA. Effect of Alternate-Day Fasting on Weight Loss, Weight Maintenance, and Cardioprotection Among Metabolically Healthy Obese AdultsA Randomized Clinical Trial. JAMA Intern Med. Published online May 01, 2017. doi:10.1001/jamainternmed.2017.0936

I thought this article was worth discussing. I spend a fair amount of time reviewing health and fitness articles that are science-backed for this website. Try searching for “alternate day fasting” and you will see how what I mean. There is so much is written about weight loss and fasting, yet there is little information to support its benefits.

In addition to weight loss, metabolic factors were also studied. There were no health benefits in people who fasted on alternate days. In addition, the dropout rate was higher in those who tried alternate day fasting compared to those who maintained a calorie restricted diet every day.

I was happy to see this study, the thought of 500 calories a day would be difficult for me. Since there is no benefit, I will stick with my current fitness plan.

Another study in the journal of Obesity did suggest that those who followed an alternate day fast may preserve more muscle mass, “After 24 weeks of unsupervised follow-up, there were no significant differences in weight regain; however, changes from baseline in % fat mass and lean mass were more favorable in alternate day fast”

One way to combat muscle loss when dieting is to participate in weight training.

What do you think of alternate day fasting?

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