Key Insights Challenge Popular Diet Trend (Image Credits: Unsplash)
A major analysis of clinical trials has found that intermittent fasting delivers weight loss results comparable to standard diets or even no intervention at all for overweight and obese adults.[1][2]
Key Insights Challenge Popular Diet Trend
Researchers led by Luis Garegnani at the Italian Hospital of Buenos Aires examined data from 22 randomized controlled trials involving nearly 2,000 participants aged 18 to 80.
These studies spanned North America, Europe, China, Australia, and South America, with follow-ups lasting up to 12 months. The review compared intermittent fasting against traditional calorie-restricted diets and a control group that made no changes.[3]
Results revealed no meaningful difference in weight reduction. Participants using intermittent fasting lost about 3 percent of their body weight on average – below the 5 percent threshold experts consider clinically significant. Garegnani noted in a press release that the approach offered no advantage over conventional methods.[1]
Types of Intermittent Fasting Under Scrutiny
The trials tested various intermittent fasting protocols, each restricting eating patterns in distinct ways.
- Time-restricted eating, such as the 16:8 method, where meals occur within an eight-hour window followed by 16 hours of fasting.
- 5:2 diet, involving normal eating five days a week and severe calorie cuts on two non-consecutive days.
- Alternate-day fasting, alternating between feast days and very low-calorie days.
- Periodic fasting, with longer fasts spaced out over time.
Despite these variations, none outperformed standard dietary advice when grouped by gender or fasting style. Inconsistencies in trial quality and participant adherence further clouded the picture.[2]
Experts Weigh In on the Evidence
Luis Garegnani emphasized the findings plainly: “Intermittent fasting just doesn’t seem to work for overweight or obese adults trying to lose weight.” He added that it is “not a miracle solution” but could suit some individuals alongside broader obesity strategies.[1]
Satchidananda Panda, a fasting researcher, questioned the review’s foundation, pointing out that most studies failed to verify if participants stuck to the regimens. “It’s a bit like building a cathedral on quicksand,” he remarked.[1] Other specialists, like Maik Pietzner from the Berlin Institute of Health, aligned with the modest outcomes, noting bodies adapt well to food scarcity but show limited benefits from short fasts.
Experts from Stanford and Cleveland Clinic stressed that sustainable weight loss hinges on overall calorie intake, diet quality, exercise, and sleep rather than timing alone.[3]
Limitations and Future Directions
The review highlighted several shortcomings in the underlying research. Many trials suffered from poor design, short durations, and no measures of satisfaction or long-term adherence. None assessed quality-of-life improvements robustly.
Animal studies hint at benefits like better insulin sensitivity and reduced inflammation, but human evidence remains weak. Timing aligned with circadian rhythms might influence outcomes, yet trials rarely accounted for this.
While the focus stayed on weight loss, intermittent fasting’s effects on other health markers – like heart disease risk or gut health – require more investigation.
Key Takeaways
- Intermittent fasting yields about 3% weight loss, similar to no diet or standard calorie counting.
- No superiority shown across fasting types or demographics in short-term trials.
- Calorie deficit and lifestyle changes drive results more than meal timing.
This Cochrane review, published in the New Scientist, urges realistic expectations amid fasting’s media buzz. Sustainable habits trump trends for lasting change. What approach has worked best for your weight goals? Share in the comments.[1]
