In recent years, high-protein diets that fall under the "paleo" umbrella have become more popular. Many of them focus on replacing carbohydrates with protein, reasoning that the body digests it more slowly—so you feel fuller for longer—and that it helps build and repair your working muscles (as long as you follow these 3 protein rules).
These diets, which generally stress foods that can be hunted, gathered or fished, is based on the theory that our bodies are designed to eat like our caveman ancestors; they're not designed to digest the processed foods that are the basis of the standard American diet. They generally advocate sticking with various grass-fed meats, wild fish, poultry, eggs, nuts, fruit and vegetables—which are generally high in protein and fiber and low in carbohydrates—and avoiding grains and starchy vegetables. Healthy fats are also recommended.
The upside: You may feel better overall and lose some inches around the waist as you cut out empty calories from processed foods. You won't go hungry. Studies have shown that people who eat more protein—about 30 percent of total calories—are less hungry and take in less calories. And studies have shown that those who upped their protein intake were 50 percent less likely to regain the weight they'd lost. They also lowered their percentage of body fat.
Are these diets right for new runners? Because these diets are so high in fiber, your digestive health may improve, but it may be tough to get through a long run without a few pit stops, or hitting the wall. Because these diets are very low in carbs and higher in fat, they're not the best choices for runners. The body runs most efficiently when it's using carbs for fuel; the body has a harder time converting fat to fuel. So you may feel sluggish while you're adjusting to this new diet. And if you're running longer distances—say up to a 10K or a half marathon—it may be challenging to find any sports energy gels or chews that meet the parameters of the diet.
A diet is commonly classified as a "detox" if it involves a change of eating patterns with the goal of ridding the body of toxin buildup. These types of diets vary from those that involve a two-day fast to others that call for a 21-day detox, during which time dieters must eliminate certain food groups or even drink "cleansing" beverages on a daily basis. Generally these diets promise quick weight loss, healing, cleansing and a renewed sense of better health. While not all detox diets are solely focused on weight loss, the eating is so restrictive that weight loss often follows.
The upside: Quick results; because you're consuming so little, the weight immediately drops off.
Are these diets right for new runners? Generally speaking, it's best to avoid these kinds of diets. While you may lose weight in the short term, they don't nurture the kind of lifestyle change and nutrition improvement that are essential to losing weight and keeping it off. Plus, you won't have the energy you need to exercise, which is critical to sustainable weight loss. Probably the most frustrating part of these diets is that once you finish the detox and return to your old eating habits, the weight you worked so hard to lose is certain to return.