Background: Based on concern about the widespread increase in being overweight and obesity along with a substantial demand for leanness, we wanted to estimate body mass index (BMI) and the prevalence of weight change attempts in a population-based sample of Norwegian women. Furthermore, we wanted to examine how weight loss attempts are related to BMI and to age, socioeconomic status, reproductive factors, lifestyle and diet.
Methods: A nationwide, cross-sectional study applying a mailed questionnaire was used. Out of a random sample of 20,000 women aged 45-69 years 10,249 women participated.
Results: Based on self-reported data, the mean BMI was 24.6 kg m-2 and 40% of the women had a BMI of > or = 25 kg m-2. More than 50% of the women were trying to lose weight and weight loss attempts were very strongly associated with BMI. Age, education, income, smoking status and perception of diet's importance to health were also significant predictors of weight loss attempts. The effect of age, education and income on weight loss attempts was modified by the level of BMI. Women trying to lose weight reported a different diet than those not trying to lose weight, irrespective of BMI.
Conclusion: A large proportion of middle-aged women are trying to lose weight. BMI is predominant in explaining weight loss attempts. After adjusting for BMI, age, lifestyle and socioeconomic status also contribute to explaining weight loss attempts.