UNIVERSITY OF CALGARY
Study shows intermittent fasting is effective for people with Crohn's disease who want to lose weight

As a diet trend, intermittent fasting has become popular and now researchers at the University of Calgary and University of British Columbia, Okanagan Campus (UBCO) have found it can have health benefits for those with Crohn's disease who want to lose weight. 

In the study, published in Gastroenterology, participants were randomized into two groups: a fasting group and a control group. The time-restricted feeding group fasted for 16 consecutive hours per day, six days per week, for 12 weeks. They ate their typical diet during an eight-hour window of time. Controls continued their usual unrestricted eating pattern. 

Maitreyi Raman. Photo Credit: Riley Brandt, University of Calgary

"The people who fasted lost weight and visceral fat, which is fat that is stored deep within the abdomen that surrounds the organs. More importantly, they had reduced inflammation throughout the body and reported fewer symptoms," says Dr. Maitreyi Raman, MD, a gastroenterologist and associate professor at UCalgary's Cumming School of Medicine, and principal investigator of the study. "Maintaining a healthy body weight for people with Crohn's disease is very important."

Crohn's disease is a form of inflammatory bowel disease (IBD). It is often complicated by excess visceral fat, which is linked to increased inflammation, reduced response to medications like biologic therapies, and places patients at higher risk surgical complications. Despite this, lifestyle strategies that specifically target body fat and metabolic abnormalities such as insulin resistance have been understudied for people with Crohn's disease.

Eating patterns may impact metabolism and microbiome

"We wanted to see whether intermittent fasting could help this particular group of people with Crohn's disease," says Dr. Natasha Haskey, PhD, a registered dietitian and clinical researcher at UBCO, and first author of the study. "We're beginning to see how metabolic health, gut microbes and immune pathways interact and how eating patterns may help restore that balance." 

In addition to feeling better, people in the fasting group showed important improvements in their metabolism and microbiome. Proteins released from fat tissue which help control metabolism, appetite, and heart and immune health shifted in a healthier direction. "To our surprise, the gut microbiome showed changes in diversity in fasting subjects versus controls. The fasting group also had a great capacity to produce fecal short-chain fatty acids that are supportive to gut health," says Raman. 

BMI decrease noted in study

Findings also show fasting participants noticed a significant decrease in their body mass index (BMI), while those participants who did not fast maintained or increased their BMI. The majority of participants in the fasting group decreased their BMI by at least one point, with larger decline in BMI resulting in greater improvements in both gastrointestinal symptoms and inflammatory markers. The researchers say these changes occurred despite both groups consuming a similar number of calories.

"Intermittent fasting isn't a replacement for medications, and it isn't a cure," says Haskey. "But, for people living with Crohn's disease who are overweight, if may be a low-cost, accessible strategy that can complement existing treatments." 

Adds Raman: "We still have a therapeutic ceiling on the effectiveness of treatment for Crohn's disease, with up to 40 per cent of people that may not respond to medical treatments. Fasting and weight-management strategies hold the promise to break the therapeutic ceiling of current medical treatments when used in combination with usual medical treatment options." 

The study was supported by the Crohn's & Colitis Foundation through the Litwin IBD Pioneers Grant and The Inflammation, Microbiome, and Alimentation: Gastro-Intestinal and Neuropsychiatric Effects (Imagine) Chronic Disease Network. Additional acknowledgements appear in the paper.