"When you're exhausted, your body lacks the energy to do its normal day-to-day functions, which includes burning calories efficiently," says Talbott. Flavo Trim One study from the University of Adelaide in Australia suggests you may lose more weight when you work out towards the end of your menstrual cycle, as opposed to right when a new one begins. Flavo Trim Reviews That’s because the hormones estrogen and progesterone tell your body to use fat as an energy source. It may be recommended for people who are more than 30 pounds overweight. In clinical trials, people who took this drug lost an average of 5%-10% of their body weight. It works by making the person feel full and thereby decreases food intake.