Food energy cost of overweight and obesity: a model to estimate the amount of food expended for excess body weight in a community

Abstract

Over-consumption of food energy entails body fat accumulation, overweight, obesity and increased risks of diseases. It is also indirectly associated with poor body condition followed by forced rest periods and limitations of activities and tasks. At community or global level, excess body weight could indirectly influence the environment by advancing food demand and the pressure on food production resources. The extent to which the environment is impacted can be estimated based on the level of excess food produced and consumed at community level. In order to determine the extra food energy required to produce and maintain excess weight, two mathematical models are designed. The concept of food energy partition, a method of determining excess weight in gender and age classes plus some information on the conversion efficiency of food energy to body fat, energy value of body fat, energy value of food, and total energy expenditure for excess weight are considered and applied in order to achieve the desired goal. Together with the affected size of a population, it was possible to estimate the additional cost of food energy for overweight and obesity. As an example, average extra global food energy expended for the excess weight in the existing population is calculated as 659.495 million Gcal (Gcal = 1000Mcal) or 261.681 million tons and that for the maintenance of excess body weight or the total energy expenditure for excess bodyweight, as 239.8 million Gcal/year or 95.07 million tons per year. Assuming that the global average annual food production per hectare is 2.64 tons, 95.07 million hectare land is required for the production of food to meet the cost for excess body weight, and 36.43 million hectare per year to meet the cost of the maintenance of the excess body weight. These values form the basis for the estimation of the extra load on environmental resources and impacts in terms of soil, water- and atmosphere degradation and the indirect influence on health and wellbeing. Considering the wide range of variability in body structure and food type and quality in the world, which could inflict relatively higher analytical error, the model is best fit to small communities with minor inherent and treatment differences.