A recent commentary from the Journal of the American Dietetic Association outlines the concept of “energy gap” and how it relates to weight loss and weight maintenance. The term energy gap was coined to estimate the change in energy balance (intake and expenditure) behaviors required to achieve and sustain weight loss in individuals and populations. There are essentially 2 concepts discussed in this paper;
1. Prevention of excess weight gain, and
2. Maintenance of achieved weight loss.
- It is estimated that the energy gap for prevention of weight gain among those who have lost weight is about 100 kcal/day in adults and 100-150 kcal/day in children and adolescents.
- Any combination of increased energy expenditure and decreased energy intake of 100 kcal per day in adults and 100-150 kcal/day for children and adolescents could theoretically prevent weight regain in 90% of the US population.
- This suggests that this small changes approach could be very effective for preventing excessive weight gain in adults and children.
- The energy gap to maintain weight loss is generally much larger, amounting to 200 kcal/day for a 100 kg person losing 10% of body weight or 300 kcal/day for the same person losing 15% of body weight.
According to obesity researcher James O. Hill, large behavioural change is required to maintain substantial weight loss, whereas smaller behavioural changes can eliminate the small energy imbalance that occurs before the body has gained substantial weight. Hill also adds;
Because the body has not previously stored this ‘new’ excess energy, it does not defend against the behavioural strategies as happens when the body loses weight.”
Simple as the concept of energy gap may seem, it’s never a bad idea to get back to basics in terms of the front line interventions for both preventing and shedding excess weight. Further, this data helps formulate more specific strategies rather than a generic “eat less, exercise more” – allowing for more specific nutritional, exercise and (very importantly) behavioural strategies to combat obesity.
Weight loss (fat loss) is simple but not easy – losing fat and maintaining it are different animals. With a long term success rate hovering around 5%, it is time to look at more permanent and effective strategies for keeping weight off.