A tough type of fast weightlifting burns more belly fat than slow weightlifting, probably because it makes your body work harder and release more fat-burning hormones.

A tough workout called HN helps young men lose belly fat after 13 weeks, while an easier workout called LST doesn't really help with fat loss. The tough workout works better because it makes your body work harder and releases special chemicals.

Doing gentle weight training slowly twice a week for 13 weeks makes young men's muscles about 7% bigger and 33% stronger, almost as much as regular heavy lifting, which made muscles 9% bigger and 41% stronger.

When doing slow, gentle weight training for your whole body, your muscles get just as tired and produce the same chemical buildup as fast, hard training—even though you're not lifting as heavy. This means your body is working hard in a different way to make the exercise effective.

Doing slow, low-intensity weight training twice a week for about three months can build muscle and strength almost as well as fast, heavy lifting in young men who don't normally exercise.