This statement is far from the truth. According to the Weight-control Information Network, lifting weights or doing strengthening activities like push-ups and crunches on a regular basis can actually help you maintain or lose weight. These activities can help you build muscle, and muscle burns more calories than body fat. So if you have more muscle, you burn more calories—even sitting still. Doing strengthening activities 2 or 3 days a week will not “bulk you up.” Only intense strength training, combined with a certain genetic background, can build very large muscles.
In addition to doing moderate-intensity physical activity (like walking 2 miles in 30 minutes) on most days of the week, try to do strengthening activities 2 to 3 days a week. You can lift weights, use large rubber bands (resistance bands), do push-ups or sit-ups, or do household or garden tasks that make you lift or dig. Strength training helps keep your bones strong while building muscle, which can help burn calories.