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.

The present study describes the trajectory of the energy gap (energy imbalance) in the Canadian population from 1976 to 2003, its temporal relationship to adult obesity, and estimates the relative contribution of energy availability and expenditure to the energy gap. It also assesses which foods contributed the most to changes in available energy over the study period.

Annual estimates of the energy gap were derived by subtracting population-adjusted per capita daily estimated energy requirements (derived from Dietary Reference Intakes) from per capita daily estimated energy available (obtained from food balance sheets). Food balance sheets were used to assess which foods contributed to changes in energy availability. Adult obesity rates were derived from six national surveys. The relationship to the energy gap was assessed through regression analysis.

Between 1976 and 2003, per capita daily estimated energy availability increased by 18 % (1744 kJ), and increased energy availability was the major driver of the increased energy gap. Salad oils, wheat flour, soft drinks and shortening accounted for the majority of the net increase in energy availability. Adult obesity was significantly correlated with the energy gap over the study period.

The widening energy gap is being driven primarily by increased energy availability. The food commodities driving the widening energy gap are major ingredients in many energy-dense convenience foods, which are being consumed with increasing frequency in Canada. Policies to address population obesity must have a strong nutritional focus with the objective of decreasing energy consumption at the population level.