All types of foods have some impact on your metabolism, good or bad. Some foods can have a more notable effect in boosting metabolism, making them beneficial for fat-burning and weight loss. According to research published in ‘The journal of Medical Investigation’, oolong tea contains approximately half the caffeine of green tea and increases energy expenditure twice as much as green tea. Another study, that appears in ‘The Journal of Nutrition’, has found that oolong tea increases metabolic rate and fat oxidation in men. To best prepare oolong tea, use loose leaf tea instead of tea bags and aim for a water temperature of 82-93°C. Steep the leaves for 1-2 minutes, depending on your preference, in a covered pot. You can steep the leaves multiple times.