A self-determination theory approach to adults’ healthy body weight motivation: A longitudinal study focussing on food choices and recreational physical activity

Abstract

This study focuses on body weight motivation based on self-determination theory. The impact of body weight motivation on longitudinal changes in food choices, recreational physical activity and body mass index was explored. A sample of adults (N = 2917, 47% men), randomly selected from the telephone book, completed a questionnaire in two consecutive years (2012, 2013), self-reporting food choices, recreational physical activity and body weight motivation. Types of body weight motivation at T1 (autonomous regulation, introjected regulation, and external regulation) were tested with regard to their predictive potential for changes in food choices, recreational physical activity and body mass index (BMI). Autonomous motivation predicted improvements in food choices and long-term adherence to vigorous recreational physical activity in both genders. Introjected motivation predicted long-term adherence to vigorous recreational physical activity only in women. External motivation predicted negative changes in food choices; however, the type of body weight motivation had no impact on BMI in overweight adults in the long term. Autonomous goal-setting regarding body weight seems to be substantial for healthy food choices and adherence to recreational physical activity.

Keywords:

• body weight motivation
• self-determination theory
• recreational physical activity
• food choices
• body mass index
• longitudinal

Notes

1. Swiss Federal Statistical Office (2010).

2. Switzerland has four national languages (German, French, Italian, Rumantsch). Of Switzerland’s population, about 65% are German-speaking, 23% are French-speaking, 8% are Italian-speaking and are .5% Rumantsch-speaking (Swiss Federal Statistical Office, 2012). German-speaking and French-speaking people represent the majority of Switzerland’s population and thus were the only ones included in the study.

3. The aim was to assess motives for why people try to regulate weight, and the authors are aware that a subjective perception of a healthy weight is not necessarily equal to an objective perception of a healthy weight.

4. According to the GPAQ analysis guide, values of less than 10 min of vigorous or moderate PA are considered as negligible and respondents are categorised as inactive. Therefore, 10 min per week of moderate PA (4 METs × 10 min = 40 METs-min) and 10 min per week of vigorous PA (8 METs × 10 min = 80 METs-min) are considered as cut-off values for moderate PA and vigorous PA, respectively.

Additional information

Funding

The Swiss Federal Office of Public Health supported Christina Hartmann.