What are intermittent fasting benefits compared with continuous dieting?

An Australian study compared continuous dieting with intermittent fasting benefits in overweight women.

According to the World Health Organization (WHO), obesity has nearly tripled worldwide since 1975. In 2016, 39% of adults were overweight and 13% were obese. Obesity is preventable. Dietary restriction is one of the key lifestyle interventions to reduce weight and lower the risk of developing type 2 diabetes or cardiovascular disease.

Unfortunately, many people find it difficult to keep to continuous dietary restrictions. Different patterns of dieting may have different benefits for weight loss and metabolic and cardiovascular health. Researchers in Australia compared continuous dieting with intermittent fasting benefits in overweight women. They recently reported their findings in the journal Obesity.

The researchers recruited 88 overweight or obese women, aged between 35-70 years. The participants were randomized into four diet groups:

1. Intermittent fasting (IF) with a diet of 70% of their calculated energy needs on non-fast days (IF70 group)
2. IF with a diet of 100% of their energy needs on non-fast days (IF100 group)
3. Continuous reduced diet at 70% of their energy needs (no fast days) (DR70)
4. Control group (100% of their energy needs, no fast days)

All groups were provided with prepared calorie-measured meals, comprising 35% fat, 15% protein, and 50% carbohydrate, which is typical for an Australian diet. The IF groups fasted for 24 hours following breakfast on three non-consecutive days per week. After a lead-in of two weeks, the participants followed their diet for 8 weeks. The researchers measured participants’ weight and body composition, and blood markers of metabolic and cardiovascular health including lipids and insulin sensitivity.

After eight weeks, the IF70 group had significantly greater reductions in weight and fat mass and improved blood markers of metabolic and cardiovascular health compared to the IF100 and the DR70 groups.

“By adhering to a strict pattern of intermittent fasting and dieting, obese women have achieved significant weight loss and improvements in their health” said Dr. Amy Hutchison, the lead author of the study. “The most successful participants lost approximately 0.5 to 1 kg per week for each week of the study,” she added.

“This study is adding to evidence that intermittent fasting, at least in the short term, may provide better outcomes than daily continuous diet restriction for health and potentially for weight loss,” said Associate Professor Leonie Heilbronn from the University of Adelaide. However, she did note that more research is needed regarding the underlying signal for limiting people’s appetite, which could hold the key to triggering effective weight loss.

Written by Julie McShane, Medical Writer

References:

1. Hutchison AT, Liu B, Wood RE, et al. Effects of intermittent versus continuous energy intakes on insulin sensitivity and metabolic risk in women with overweight. Obesity Vol 27, Number 1; Jan 2019.
2. Press release: “Intermittent fasting could improve obese women’s health.” University of Adelaide. https://www.adelaide.edu.au/news/news104242.html