Research carried out at the University of Adelaide shows that obese women lost more weight and improved their health by fasting intermittently while following a strictly controlled diet.
The study, published in the journal Obesity, involved a sample of 88 women following carefully controlled diets over 10 weeks.
"Continuously restricting their diet is the main way that obese women try to tackle their weight," says Dr Amy Hutchison, lead author from the University of Adelaide and the South Australian Health and Medical Research Institute (SAHMRI).
"Unfortunately, studies have shown that long-term adherence to a restricted diet is very challenging for people to follow, so this study looked at the impact of intermittent fasting on weight loss.
"Obese women who followed a diet in which they ate 70% of their required energy intake and fasted intermittently lost the most weight.
"Other women in the study who either fasted intermittently without reducing their food intake, who reduced their food intake but did not fast, or did not restrict their diet at all, were not as successful in losing weight," says Dr Hutchison.
The study also checked the effect of the different diets on the women's health. Women who fasted intermittently as well as restricting their food improved their health more than those who only restricted their diet or only fasted intermittently.
"By adhering to a strict pattern of intermittent fasting and dieting, obese women have achieved significant weight loss and improvements in their health such as decreased markers for heart disease," says Dr Hutchison.
Participants who fasted intermittently ate breakfast and then refrained from eating for 24 hours followed by 24 hours of eating. The following day they fasted again.
All participants of the study were women who were overweight or obese with a Body Mass Index (BMI) in the 25-40 range and aged between 35 and 70 years. They followed a typical Australian diet consisting of 35% fat, 15% protein and 50% carbohydrate.
"The most successful participants lost approximately 0.5 to 1 kg per week for each week of the study," says Dr Hutchison.
"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," says Associate Professor Leonie Heilbronn from the University of Adelaide and SAHMRI.
"While the study confirms that intermittent fasting is more effective than continuous diet restriction, the underlying signal for limiting people's appetite, which could hold the key to triggering effective weight loss, requires further research."
New trials now being undertaken will examine the effectiveness of long-term fasting on both men and women.