Obesity is having an excessive amount of body fat.

Body mass index (BMI) : weight (kg) / [height (m)]2

Less than 18.5                 Underweight

From 18.5 to 24.9           Normal

From 25.0 to 29.9          Overweight

30.0 or higher                Obesity

It increases the risk of heart disease, diabetes, high blood pressure and certain types of cancer.

There are many reasons why some people have difficulty losing weight. Obesity is generally the result of physiological and environmental factors combined with diet, physical activity, and exercise choices.

Energy input/Food

Spending energy/Physical activity