Real talk: It could take weeks or months to see the metabolic effects of exercise on the scale, and even then, building muscle, which is denser than body fat, could lead to weight gain. "Do what you like because it’s good for you," Dr. Seltzer says, noting the way exercise is awesome for your heart, mental health, and more—and that not all measure of progress can be seen on the scale.

The next time you train that muscle group, decrease the starting weight by 5-10 pounds. If any of the HIIT 100s exercises are new to you, you'll need to spend some time figuring out how much weight you can do for 10 reps. The week before you start the HIIT 100s program, work these exercises into your training to get a gauge on appropriate weights. When estimating your 10RM, be sure to do the HIIT exercise first for that muscle group.
Drink sugar water once a day. This brain hack works by suppressing production of the hunger hormone ghrelin and is a small exception to the no sugar rule above. It was discovered by the late Dr. Seth Roberts, and tested and verified by Drs. Stephen Dubner and Steven Levitt, of Freakonomics fame. Done properly, it has a dramatic appetite-suppressant effect, making your diet much easier to follow.
The popular "flat belly diets"embrace much of the wisdom found in eating a Mediterranean diet, which helps everything from brain health to hearth health. The basic premise for both diets is eat foods rich in monosaturated fatty acids (MUFA) that may help reduce your belly fat storage. MUFA-rich foods include olive oil, nuts and seeds, avocodos, and fish. Eating yogurt regularly has also been found to be helpful in reducing belly fat.