(LB03-28-26) Changes in Diet Quality During a 12-Week Behavioral Weight Loss Intervention in Adults Aged >50 With Overweight or Obesity

Objectives: Behavioral weight loss interventions emphasize energy restriction and weight change, yet its impact on diet quality remains underexplored, particularly in older adults with overweight/obesity. This study examined changes in diet quality and micronutrients of concern during a 12-week behavioral weight loss intervention promoting a hypocaloric diet and increased water intake in adults aged >50 with overweight or obesity and low habitual plain water intake ( < 6 cups/day).

Methods: This was a sub-analysis of an ongoing randomized controlled trial exploring water intake and weight control in adults aged >50. Participants were randomized to one of three groups for 12 weeks: pre-meal water consumption (500 mL 3x/d, before each meal), daily water intake (>1500 mL/day), or a control group (no water intake prescription). All groups received Social Cognitive Theory-based behavioral counseling and a hypocaloric diet prescription with weekly dietary counseling. Diet quality was assessed using the Healthy Eating Index (HEI)-2015, derived from three 24-hour dietary recalls at baseline and week 12, and analyzed with Nutrition Data System for Research software.

Results: All participants (n=86; 73% F; 61±7 years; BMI=33±5 kg/m²) improved HEI-2015 total scores from 56+11 to 63+12 (p < 0.05), with no group-by-time interaction. In the pooled sample, improvements in five HEI sub-component scores were observed: total fruits (2.0+1.3 to 2.5+1.5), whole fruits (2.4+1.6 to 3.2+1.6), whole grains (4.5+2.6 to 5.7+3.2), refined grains (6.7+2.7 to 7.8+2.1), and added sugars (8.3+1.9 to 9.1+1.2) (all p< 0.05). There were no group by time differences in HEI sub-scores. Reported dietary intake of calcium and vitamin D did not change, yet intakes were below recommendations (792+290 and 4.0+4.7 compared to the recommended 1200 and 15 mcg, respectively).

Conclusions: Participation in a behavioral weight loss intervention utilizing a hypocaloric diet can improve overall diet quality in adults aged >50, but targeted strategies may be needed to address micronutrient inadequacies.

Funding Sources: R01 DK135410