Nutrient intake during diet-induced weight loss and exercise interventions in a randomized trial in older overweight and obese adults

Dietary restriction in obese older adults undergoing weight loss may exacerbate nutrient deficiencies common in this group; the nutritional health of older adults is a factor in their quality of life, disability, and mortality. This study examined the effect of an 18-month weight loss program based in social cognitive theory incorporating partial meal replacements, on nutrient intake in older overweight and obese adults. The following analysis is from the Intensive Diet and Exercise for Arthritis (IDEA) trial, a single-blind, randomized controlled trial. Individuals were randomized into one of three 18-month interventions: exercise (E); intensive diet-induced weight loss (D); or intensive diet-induced weight loss plus exercise (D+E). The study setting was at a university research facility. Overweight and obese older adults (n=388; BMI=33.7 +/- 3.8 kg/m2; 65.8 +/- 6.1 years) were recruited. The D and D+E interventions (group mean goal of 10% loss by 18-months) utilized partial meal replacements (2 meal replacement shakes/day for 6-months). Exercise training for E and D+E was 3 days/week, 60 minutes/day. Three day food records were collected at baseline, 6-months, and 18-months and analyzed for total energy and macro- and micronutrient intake. Comparisons of dietary intake among treatment groups were performed at 6 and 18 months using mixed linear models. Weight loss at 18-months was 11.3 +/- 8.3% (D), 10.3 +/- 6.8% (D+E), and 1.2 +/- 4.2% (E). Meal replacements were used by more than 60% (6-months) and 50% (18-months) of D and D+E participants, compared to 15% for E. Both D and D+E consumed less energy and fat, and more carbohydrates and selected micronutrients than E during follow-up. More than 50% of all participants consumed less than the recommended intake of particular vitamins and minerals. The diet intervention improved intakes of several nutrients. However, inadequate intake of several vitamins and minerals of concern for older adults suggests they need further guidance to assure adequate intake.