FRIDAY, Jan. 9, 2026 (HealthDay News) -- Nutritional guidance to support safe weight loss is frequently lacking for adults with obesity or type 2 diabetes receiving semaglutide or tirzepatide, according to a study published online Jan. 8 in Obesity Reviews.Marie Spreckley, Ph.D., from the University of Cambridge in the United Kingdom, and colleagues conducted a systematic scoping review of studies published between January 2015 and April 2025 to map and appraise clinical trials incorporating nutritional interventions or dietary assessments during semaglutide or tirzepatide therapy in adults with obesity or type 2 diabetes.Twelve studies were included in the review: 10 randomized controlled trials, one nonrandomized comparative study, and one cross-sectional observational study. Interventions varied from structured very-low-energy or ketogenic diets to general lifestyle counseling and observational dietary assessments. The researchers found a decrease in energy intake by 24 to 39 percent across studies, but up to 40 percent of total weight reduction was accounted for by lean tissue loss. Nutrition professionals were involved in only three studies; systematic assessment of protein or macronutrient intake occurred rarely. Widespread nutrient inadequacies and limited access to dietetic support were found in one observational study."If nutritional care is not integrated alongside treatment, there's a risk of replacing one set of health problems with another, through preventable nutritional deficiencies and largely avoidable loss of muscle mass. This represents a missed opportunity to support long-term health alongside weight loss," Spreckley said in a statement.Two authors disclosed ties to the pharmaceutical industry; one author disclosed ties to Reset Health Clinics Ltd.Abstract/Full Text.Sign up for our weekly HealthDay newsletter