The prevalence of overweight and obesity is increasing in most countries, including Germany. The idea of estimating the population-wide energy gap that is likely responsible for the epidemic has recently been introduced and discussed.

Using published estimates of body weight from population-based data of national health surveys (1985–2002), the energy gap was calculated by estimating the distribution of the rate of weight gain within the German population (25–69 years of age) and the amount of excess energy storage that is responsible for this population-wide pattern of weight gain.

Germany.

A representative sample of 26 614 participants (12 984 men, 13 630 women).

The average annual weight gain was 0·22 kg for men and 0·32 kg for women over the 17-year period. An estimated 90 % of the population gained < 0·54 kg/year. Assuming that each kilogram of weight gained represents 32238 kJ (7700 kcal), the estimated energy accumulation was 19 kJ (4·64 kcal)/d in men and 28 kJ (6·75 kcal)/d in women aged 25–69 years. The distribution of estimated energy accumulation for 90 % of the German population was < 50 kJ (12 kcal)/d.

With an assumed energy efficiency of 50 %, the findings suggest that weight gain could be prevented in 90 % of the German population with < 100 kJ (24 kcal) reduction in energy intake or increase in energy expenditure per day. Theoretically, further weight gain might be prevented using a small-changes approach that emphasizes the importance of making small changes in physical activity and food intake.