Fasting May Not Work Better Than Other Diets

Punishing fast days may not provide the payoff that advocates think. A new review from the Cochrane Collaboration of 22 clinical trials involving nearly 2,000 adults finds that intermittent fasting—whether alternate-day plans, 5:2 diets, or time-restricted eating—produced about 3% weight loss on average, below the 5% threshold doctors consider clinically meaningful, reports the Guardian. Traditional calorie-cutting approaches performed about the same, with no clear advantage for fasting. "It doesn't appear clearly better, but it's not worse either," says lead author Dr. Luis Garegnani, director of the Cochrane Associate Centre at the Italian hospital of Buenos Aires in Argentina.

Perhaps most striking is that study participants who did nothing, the control group, lost about 2% of their original weight, a difference not considered statistically significant from the fasters, per the Conversation. One caveat is that the research into fasting as a weight-loss technique is still emerging, and these were all short-term studies in the review. Thus fasting might well be a "safe and effective way" to manage weight for some, notes the Conversation, depending on individual needs and the guidance of a doctor. Still, this particular review suggests "the current evidence doesn't justify the enthusiasm we see on social media," says Garegnani in a statement.