Of all the ways to lose weight, Yang recommends the traditional way: a balanced diet, smaller portions, lower fat, carbs and sweets, and regular physical exercise.

All food groups provide important nutrition, so do not eliminate any group. To lose weight, the body needs to burn carbohydrates,  a favorite target of dieters. So reduce, don't eliminate. A long-term diet without carbohydrates can lead to metabolic disorders.

If you're trying to lose weight, eat a balanced diet with smaller quantities in each category, says Yang.

He suggests at least 30 minutes daily of aerobic exercise, like jogging and brisk walking. Heavy exercise burns more glycogen (a polysaccharide that converts to sugar) than fat, he says.

That's why after you have warmed up at the gym, steady walking on a treadmill is a good way to burn calories.

The TCM take

Traditional Chinese medicine has a different take on weight loss. Not only is it caused by eating too much, but it also can be caused by spleen problems. Spleen in TCM refers to the entire digestive system.

"A well-functioning spleen not only helps in absorbing nutrition but also in expelling excessive fluid," says Dr Zhang Zhongyi, chief of the Acupuncture Department of Yueyang Western and Traditional Chinese Medicine Hospital.

Spleen problems mean excessive fluid collects and turns to fat.

Many middle-aged people gain as their spleen function declines with age. Not eating regular meals but frequently snacking can cause digestive problems leading to overweight, especially in young women.

Exercise regularly and eat spleen-reinforcing foods. They include Pu'er tea, chen pi (dried orange peel) tea, pearl barley, yams and white gourd.

Acupuncture to improve the spleen/digestive system is popular and effective and can help girls of normal weight who insist on losing more, Dr Zhang says.

BMI

BMI = weight (kg) / (height (m) * height)

Body mass index is the most widely used diagnostic tool to identify obesity problems in adults.

BMI is a measurement of body weight based on height and weight. It applies to both adult men and women. There are many calculators online.

By WHO standards, a BMI of less than 18.5 is underweight and may indicate malnutrition, an eating disorder, or other health problems. A BMI over 25 is consider overweight and above 30 is considered obese.

BMI does not predict health.