Physical activity and dietary behavior change in Internet-based weight loss interventions: comparing two...

Area of Science:

• Health behavior change
• Obesity interventions
• Digital health

Background:

• Overweight and obesity are significant public health concerns.
• Effective weight loss interventions often require modifications in both physical activity (PA) and dietary habits.
• Internet-based interventions offer scalable solutions for behavior change.

Purpose of the Study:

• To evaluate the effectiveness of two Internet-based weight loss interventions.
• To assess changes in physical activity and dietary behaviors.
• To compare two distinct methods for quantifying combined behavior change.

Main Methods:

• 352 overweight/obese adults participated in 12-month Internet-based interventions.
• Physical activity (PA) and sedentary time were measured using accelerometers.
• Dietary intake (fat, fruits, vegetables) was assessed via food frequency questionnaires.
• Combined behavior change was analyzed using the standardized residualized change index (SRCI) and risk factor change index (RFCI).

Main Results:

• Interventions significantly improved combined physical activity and dietary behaviors (p<0.001).
• The SRCI demonstrated a larger intervention effect (β=0.30) compared to the RFCI (β=-0.18).
• Both measurement approaches indicated significant positive intervention effects.

Conclusions:

• Internet-based interventions targeting both physical activity and diet are effective for weight management.
• The SRCI is a more sensitive metric for evaluating intervention impact.
• The RFCI may be more practical for communicating public health outcomes.