Since most of us are in positive energy balance, and consequently gain weight slowly but gradually over time, the present results are highly relevant for most Western populations. (sciencedaily.com)
This is called positive energy balance or a calorie surplus and is the reason why people become overweight (except for some medical conditions). (instantknockout.com)
Over weeks, months, or years, a small cumulative impact of sustained positive energy balance results in weight gain and obesity (10). (pnas.org)