Green tea is a popular weight loss supplement. A controlled study published in the Journal of American College Nutrition, reported that green tea or green tea extract supplements reduced body fat and prevented oxidative cell damage in obese people with the metabolic syndrome (eg. high blood pressure, abdominal fat deposition, insulin resistance, abnormal blood fats). People lost an average of 5.5lb of fat and reduced BMI (Body Mass Index, measure of the proportion of weight to height) by 1.9 points. Green tea (4 cups per day) or green tea extract (2 tablets per day) improved metabolic health in obese people.
A good measure of obesity is hard to find. Sophisticated measurements such as DEXA (dual energy X-ray absorptiometry), air displacement, and underwater weighing, are expensive and largely unavailable. Body mass index (BMI; the proportion of weight to height) is the most common measure of fatness, but it is inaccurate in weight-trained athletes. Waist circumference is difficult for most people to measure. Researchers from the University of Michigan found that neck circumference was related to excess body fat and was a reliable predicator of obesity in children. Neck circumference was a good screening tool in children for predicting future adult health problems, such as obstructive sleep apnea, diabetes and high blood pressure.