Intermittent fasting and protein-paced dieting may have benefits beyond weight loss, according to a new study. Researchers found that combining intermittent fasting with variances in participants’ protein intake led to significant improvements in gut health and microbiome. This is one of the first studies to investigate the effects of intermittent fasting on digestive issues compared to standard calorie restriction without adjusting meal timing.
Although the sample size was quite small, this clinical trial was recently Nature CommunicationsForty-one participants were classified as overweight or obese and took part in one of two dietary interventions over eight weeks.
Participants were divided into two groups.
- Intermittent fasting and protein-paced dieting: The diet was defined as 4 meals eaten evenly spaced 4 hours apart per day, consisting of 35% carbohydrates, 30% fat and 35% protein. Each meal contained 25-50g of protein. Participants followed the plan 5-6 days per week, plus an extended fasting period of at least 36 hours each week.
- Calorie restricted dietThe diet consisted of a calorie-restricted diet consisting of 41% carbohydrate, 38% fat, and 21% protein. Meal timing was not specified, but subjects followed a “heart-healthy” diet.
Both dietary interventions reduced total intake of fat, carbohydrate, sodium and sugar, and cut calorie intake by about 40% (about 1,000 calories per day) from baseline levels. Both groups were monitored for changes in weight, body composition, gut microbiota and other biomarkers over eight weeks.
Results showed that intermittent fasting and protein pacing significantly affected the gut microbiome compared to calorie restriction alone. Participants experienced reduced symptoms of gastrointestinal issues and increased gut microbiome diversity compared to the control group. These microbes in the gut are also associated with a leaner body shape and improved health. The intermittent fasting and protein pacing protocol also increased blood proteins associated with weight loss and by-products that boost fat metabolism.
Interestingly, even though both groups had the same average weekly calorie intake, the IF and protein-paced group experienced greater weight loss and improved body composition, in addition to improved gut health.
- The IF and protein pacing group lost an average of 8.81% of their body weight.
- The calorie-restricted diet group lost an average of 5.4% of their body weight.
The IF and protein pacing group experienced increases in lean body mass (likely due to a small increase in protein intake in comparison), as well as decreases in overall body fat, abdominal fat, and deep abdominal fat.
What this means for us
Although further research is needed, this study may have implications for recommendations of dietary interventions such as intermittent fasting for improving gut health and weight management. In combination with an energy deficit, increasing protein intake and dispersing protein throughout the day is an effective way to improve satiety, maintain and increase lean body mass, and reduce fat mass.
Study limitations
This study was conducted with a relatively small sample size, which may limit the applicability of the results to a broader population. That is, participants may not be fully representative of the general population suffering from gastrointestinal symptoms or the diversity of the general population adopting a similar diet. Also, the study period was fairly short at 8 weeks, so it may not be representative of the long-term effects or sustainability of the diet used. A longer follow-up period and a larger sample size may provide more reliable long-term insights. Adherence to dietary treatments such as intermittent fasting and calorie restriction varies from person to person. This, combined with the reliance on self-reported gastrointestinal symptoms and food intake, may lead to inaccurate results. The results are interesting, but further research is needed at this time.
Kate is a fitness writer. Men’s Health UK There she contributes regular workouts, training tips, and nutrition guides. She has a Postgraduate Diploma in Sports Performance Nutrition and prior to joining Men’s Health, she spent over 5,000 hours on the gym floor as a nutritionist, fitness writer, and personal trainer. Kate has a strong interest in volunteering at animal shelters, and when she’s not lifting weights in the yard, she can be found walking rescue dogs.
