Despite these optimistic findings, calorie-restricted diets and intermittent fasting aren’t for everyone.
Nutrient density is a priority for those Crohn’s patients, for whom every calorie counts. Restricting may worsen existing nutritional gaps, says Chelsea Cross, RD, a registered dietitian and personal trainer who has Crohn’s disease and works with clients with IBD. “Already nutrients are not being optimally absorbed, so a calorie-restricted diet would just further decrease potential [for nutrients] to be taken in,” she says.
Weight loss, muscle loss, and vitamin deficiencies are the biggest risks people with Crohn’s may encounter if they try unsupervised calorie restriction diets, Ivanina says.
Nutritional deficiency risk depends on what part of the bowel Crohn’s affects. But, in general, Crohn’s patients are at higher risk for deficiencies in vitamin B12, iron, and fat-soluble vitamins (vitamin A, D, E, K), as well as muscle loss, she says.
Ivanina says certain other people with Crohn’s disease should also steer clear of fasting and calorie-restricted diets, including those with:
- Active malnutrition
- Unexpected weight loss
- More severe or escalating clinical situations, such as recent hospitalization or systemic steroid use
- A history of eating disorders or disordered eating patterns