Does intermittent fasting actually help you to lose weight?
What's the story
A major review of scientific evidence found that intermittent fasting is not more effective than traditional diets for weight loss. The researchers analyzed data from 22 global studies and saw that people who are overweight/obese lost as much weight by following conventional dietary advice as they did with fasting regimes like 5:2 diet. The review also noted that intermittent fasting was only slightly better than not dieting at all, with participants losing about 3% of their body weight through fasting.
Expert opinion
Not a miracle solution
Dr. Luis Garegnani, the lead author of the review and Director at the Cochrane Associate Centre in Buenos Aires, Argentina, said, "Intermittent fasting is not a miracle solution but it can be one option among several for weight management." He added that "intermittent fasting likely yields results similar to traditional dietary approaches for weight loss. It doesn't appear clearly better but it's not worse either."
Study details
Popularity of intermittent fasting
Intermittent fasting has gained immense popularity due to claims of its benefits for weight loss, physical and cognitive health, and even anti-aging. The Cochrane review analyzed data from some randomized clinical trials involving 1,995 adults across Europe, North America, China, Australia, and South America. These trials examined different types of intermittent fasting such as alternate-day fasting, the 5:2 diet where people fast for two days a week, and time-restricted eating.
Quality assessment
Need for more research
The researchers found no strong evidence that intermittent fasting improved people's quality of life more than other diets. Dr. Garegnani stressed the need to clarify the evidence around fasting diets given their immense popularity and widespread media promotion. He noted that many of the studies were short-term and low-quality, making it difficult to draw firm conclusions on potential benefits. Interestingly, none of the 22 studies assessed participants' satisfaction with intermittent fasting according to Garegnani's findings.
Timing impact
Potential benefits and challenges of intermittent fasting
Dr. Zhila Semnani-Azad from the National University of Singapore suggested that the benefits of intermittent fasting may depend on timing, as circadian rhythms are closely linked to metabolism. Animal studies have shown that fasting can alter fat utilization, enhance insulin sensitivity (crucial for diabetes), and lower inflammation and oxidative stress. It may also promote longevity by triggering autophagy, the body's recycling mechanism. However, there's no universal definition of intermittent fasting, making it difficult to understand its effects on health outcomes.
Fasting effects
Surprising findings on fasting and weight loss
Maik Pietzner, a health data modeling professor at the Berlin Institute of Health, was surprised by the small weight loss from fasting compared to doing nothing. He said this finding matches the evidence that people are less physically active when fasting and that weight loss is difficult without drugs. Pietzner's own research shows short periods of complete fasting have little effect on our bodies, with significant changes only observed after longer durations like three days of water-only consumption.