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 HMR Program uses meal replacements – think low-calorie shakes, meals, nutrition bars and hot cereal – in phases, coaching from experts, physical activity and an emphasis on fruits and vegetables to help dieters shed pounds fast. While last year the diet shared the No. 1 ranking in this category with the Biggest Loser diet, this year it has the top spot to itself. "This diet makes it easy to lose weight fast and would likely be effective for someone who wants to lose weight for a specific event," one expert said. "However, as far as long-term healthy-habit-forming, this diet falls short" in part because dieters don't learn to make their own healthy food choices.
The best low-cal diet plan isn't a diet so much as it is a method. CICO stands for "calories in, calories out" and is based on the mathematically sensible principle that as long as you're burning more calories than you're eating, you'll lose weight. All you need to get started is a way to track your calories—there are plenty of apps on the market although a pen and paper works great too—and a food scale to keep you honest about your portion sizes. (Also read this guide on how to safely cut calories to lose weight.) People love the simplicity and straightforwardness of the plan. And while it may not be the fastest way to lose weight, you're guaranteed to have success long term. (Just know that some weight-loss experts actually don't recommend calorie counting.)
Sure, you can lose weight quickly. There are plenty of fad diets that work to shed pounds rapidly -- while leaving you feeling hungry and deprived. But what good is losing weight only to regain it? To keep pounds off permanently, it's best to lose weight slowly. And many experts say you can do that without going on a "diet." Instead, the key is making simple tweaks to your lifestyle.