Their body weights have typically been 10% to 15% lower than those of their steel equivalents.

ECONOMIST: Tech.view: Unbearable lightness? | The

The German researchers examined the body weights and DNA of 181 relatives of 25 extremely obese patients who carried the gene mutation.

BBC: NEWS | Health | Faulty gene link to obesity risk

Instead of lifting weights he used his own body weight for resistance.

CNN: College professor goes from fat to 'Mr. Low Body Fat'

You don't have to be a bodybuilder though -- light weights or even using your own body weight for resistance is enough for beginners.

CNN: The new face of fitness is getting older

Strength training can involve a number of approaches including using free weights, such as dumbbells or barbells, resistance or elastic bands that allow you to flex using your arms and legs, as well as ankle weights or vests and other special exercises that use your body weight to simulate resistance against gravity.

FORBES: Why Strength Training May Help You Live Longer

The weights of the individual wolves were estimated based upon models derived from body-mass measurements taken concurrently from 304 wolves, including 86 of the 94 wolves in the study.

ECONOMIST: Controlling the size of predators