The basic cause of obesity and overweight is an energy imbalance between calories consumed and calories expended and maintaining your current body weight indicates you are in caloric balance and to gain or lose weight, will need the balance scale to tip in one direction or another to achieve a goal.
Whether you want to lose weight or maintain a healthy weight, the connection between the energy the body takes in, through the food and drink consumed and the energy the body uses through the activities, must be taken into consideration.
A number of factors play a role in obesity and it is a complex health issue to address - behaviour, environment,culture, socioeconomic status and genetic factors in disorders such as Bardet-Biedl syndrome and Prader-Willi syndrome - all play a part and may have an effect in causing people to be overweight and obese.
Overweight and obesity are the result of an energy imbalance where too many calories are eaten and not enough physical activity takes place.
Behaviour and environment play a large role causing people to be overweight and obese and are the greatest areas for prevention and treatment actions.
Maintaining a healthy weight for a lifetime involves balancing the number of calories consumed with the number of calories the body uses or "burns off."
A calorie is defined as a unit of energy supplied by food and is a calorie regardless of its source - carbohydrates, fats, sugars, or proteins, all of them contain calories. It takes approximately 3,500 calories below your calorie needs to lose a pound of body fat - to lose 1 to 2 pounds a week, the caloric intake must be reduced by 500-1000 calories per day.
There has been a global shift in diet towards increased intake of energy-dense foods that are high in fat and sugars but low in vitamins, minerals and other micronutrients and this along with a trend towards decreased physical activity has had a large impact on worldwide increase in obesity rates. The increasingly sedentary nature of many forms of work, changing modes of transportation, and increasing urbanization have added to the problem.