Sure, high-intensity cardio can help you torch calories, but ideally, you’ll also need to pump some iron to build metabolism-boosting muscle. That’s because strength training is one of the few activities you can do to spike the amount of calories you burn, even after you’re done with your workout. Case in point: one 2012 review of research found that while completing a 20-minute resistance training circuit may help you burn 200 calories, your body’s resting metabolic rate stays elevated for the next hour, helping you burn an additional 50 calories. Plus, when you lose weight, you lose some muscle with it, so building and maintaining that lean mass will help you achieve a more toned look.
For even more impressive effects on body composition: aim for exercise forms which elicit a positive hormonal response. This means lifting really heavy things (strength training), or interval training. Such exercise increases levels of the sex hormone testosterone (primarily in men) as well as growth hormone. Not only do greater levels of these hormones increase your muscle mass, but they also decrease your visceral fat (belly fat) in the long term.
The least intrusive weight loss methods, and those most often recommended, are adjustments to eating patterns and increased physical activity, generally in the form of exercise. The World Health Organization recommended that people combine a reduction of processed foods high in saturated fats, sugar and salt and caloric content of the diet with an increase in physical activity.
The prevailing formula for a long time on how much fat you’re going to burn was calories in minus calories out, based on your basal metabolic rate (BMR) and exercise efforts, explains strength and performance specialist Joel Seedman, Ph.D., owner of Advanced Human Performance in Atlanta. But with all the different biochemical reactions in the body, hormonal response, and endocrine function, there are an infinite number of factors that can affect how your body is storing and breaking down calories.