February 16, 2026, 12:13 pm | Read time: 4 minutes
The hype around intermittent fasting suggests that the method is superior to traditional diets; for example, there is a special “turbo effect” on metabolism or fat burning that arises solely from fasting periods. Studies in the past have already shown that the method is not a guaranteed way to lose weight. Even more sobering for proponents of intermittent fasting may be the findings of a new review.
Losing Weight? Intermittent Fasting Apparently Doesn’t Beat Other Diets
Researchers analyzed 22 randomized controlled trials with nearly 2,000 participants. Various forms of intermittent fasting (e.g., time-restricted eating, periodic fasting, or alternate-day fasting) were examined. The central findings of the study: For weight loss in overweight adults, it is not significantly more effective than conventional diets or calorie-reduced mixed diets.1
Why This Is Interesting
Weight loss is the most important strategy for reducing the health risks of obesity. While conventional calorie-reduced diets often show only short-term success, intermittent fasting is heavily promoted. However, there is great uncertainty among doctors and patients about whether the method is truly a sustainable solution for long-term weight loss. Previous study results have shown: Simply adjusting the time window is not enough if you want to lose weight. There is no “turbo effect” on fat burning or metabolism just by applying intermittent fasting. In the end, the calorie balance is what matters.
Additional context is provided by the recently published systematic review by the Cochrane Collaboration. Researchers led by Luis Garegnani from the University of the Italian Hospital of Buenos Aires searched several large medical databases up to November 2024 and included only studies with particularly high significance. A minimum intervention duration of four weeks and at least six months of follow-up were also required.
What the Researchers Found
The researchers concluded: Compared to conventional dietary advice, intermittent fasting “probably has little or no effect on weight loss.”
Even compared to people who received no treatment or were on a waiting list, there were probably few differences in weight loss, according to the study.
The researchers found that the approaches did not result in clinically significant changes in most of the endpoints studied. These included (in addition to weight loss) quality of life, side effects such as fatigue or headaches, participant satisfaction, and effects on diabetes status.
The “Gaps” in the Cochrane Analysis
Does intermittent fasting bring no benefits at all? The researchers do not explicitly say that. Their confidence in their own results is—except for weight loss vs. no treatment—very low, as many studies did not use robust methods, focused only on short-term effects (up to 12 months), or had too few participants.
In particular, health aspects in the previous high-quality studies have simply not been sufficiently investigated. For example, none of the included studies provided data on diabetes status or comorbidities.
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Liver, Microbiome, and Sleep Quality Could Benefit
There are indeed studies that suggest positive effects of intermittent fasting on health. In addition to the liver, microbiome, and blood sugar levels, sleep quality could possibly benefit.2,3 Just recently, a study with a small number of participants and short duration, focusing on Crohn’s disease patients in clinical remission with concurrent overweight or obesity, showed a reduction in abdominal discomfort and improved disease activity under intermittent fasting.4
The strategy might even help the body fight cancer cells.
Intermittent Fasting as an Easy Entry into Healthier Eating
Even if the effects are generally rather limited: Intermittent fasting is suitable for many as a practical entry into healthier eating. Methods such as 14:10, 16:8 (an eating window of ten hours or eight hours), and the 5:2 variant, where you eat normally for five consecutive days and then fast for two days, can be easily implemented in everyday life.
It is wise to carefully document which method and time window you choose—this sharpens motivation—and you should drink plenty, ideally water, tea, and vegetable broth. Exercise is also a good idea, as physical activity enhances well-being and conveys a sense of strength.