Resistance training is associated with spontaneous changes in aerobic physical activity but not overall diet quality in adults with prediabetes

Abstract

Background: Aerobic exercise interventions have been shown to result in alterations to dietary intake and non-exercise physical activity (PA). To date, the ability for resistance training (RT) to influence other health-related behaviors has not been examined. This study aimed to determine if initiation and maintenance of RT is associated with spontaneous changes in dietary quality and non-RT PA in adults with prediabetes.

Methods: Overweight/obese adults (n=170, BMI=32.9±3.8kg·m², age=59.5±5.5years, 73% female) with prediabetes were enrolled in the 15-month Resist Diabetes trial. Participants completed a supervised 3-month RT initiation phase followed by a 6-month maintenance phase and a 6-month no-contact phase. Participants were not encouraged to change eating or non-RT PA behaviors. At baseline, and months 3, 9, and 15, three 24-hour diet recalls were collected to evaluate dietary intake and quality, the Aerobics Institute Longitudinal Study Questionnaire was completed to evaluate non-RT PA, and body mass, body composition (DXA), and muscular strength were measured. At months 3, 9, and 15 social cognitive theory (SCT) constructs were assessed with a RT Health Beliefs Questionnaire. Mixed effects models were used to assess changes in dietary intake and non-RT PA over the 15-month study period.

Results: Energy and carbohydrate intake decreased with RT initiation and maintenance phases (baseline to month 9: β=-87.9, p=0.015 and β=-16.3, p<0.001, respectively). No change in overall dietary quality (Healthy Eating Index [HEI]-2010 score: β=-0.13, p=0.722) occurred, but alterations in HEI-2010 sub-scores were detected. Maintenance of RT was accompanied by an increase in MET-min/week of total non-RT PA (month 3 to month 9: β=146.2, p=0.01), which was predicted by increased self-regulation and decreased negative outcome expectancies for RT (β=83.7, p=0.014 and β=-70.0, p=0.038, respectively).

Conclusions: Initiation and maintenance of RT may be a gateway behavior leading to improvements in other health-related behaviors. These results provide rationale for single-component lifestyle interventions as an alternative to multi-component interventions, when resources are limited.

Keywords: Behavior change; Exercise; Food choices; Lifestyle modification; Spillover effect.