"It is currently unclear whether tea or tea extracts promote weight loss. Large-scale clinical trials that control for energy intake and expenditure are needed to answer this question."Are control studies really what we want here?
Western science is based around the idea of controlled studies that isolate one variable and examine the effect of changing that variable when others stay constant. But do controlled studies actually capture what happens in a practical setting? Not at all.
Drinking tea has many mechanisms by which it can influence weight loss through influencing energy intake:
- Tea is a calorie free drink. Tea can be consumed as a substitute for calorie-rich drinks such as soft drinks, milk, fruit juice, or energy drinks. In this case, drinking tea could directly reduce someone's calorie intake.
- Tea can be quite bitter, and is generally not very sweet. Drinking unsweetened tea on a regular basis could change people's tastes, making them more accustomed to foods that are less sweet. This could reduce their calorie intake through reducing refined sugars in their diet.
- Tea contains caffeine, which is known to reduce appetite. Tea also contains a myriad of other chemicals, many of which are poorly understood. It is reasonable that tea could have other effects on appetite and food preferences beyond those caused by caffeine as well. Either way, drinking tea is likely to lead people to reduce their calorie intake overall.
Oh, and one last observation--tea extracts do not have the first and second benefit above. Actually drinking tea is necessary to get the full weight-loss potential, since part of the way tea can help you lose weight is through the act of drinking and tasting it, not just through chemicals that you can pop in a pill.