context: Drop 10 pounds in one week and never gain it back. You can do it if you follow the Dukan Diet's rules, claims French general practitioner and nutritionist Pierre Dukan, who created the diet in 2000. Lean protein, oat bran, water, and a daily 20-minute walk are at the heart of the plan. The theory is that limiting carbohydrates forces your body to burn fat. Basically, you can eat unlimited quantities of food, as long as they're on the approved foods list, which includes very few carbs, if any. You'll be eating a lot of protein and oat bran. The diet has four phases. During the â Attackâ phase (1-10 days), you eat all the lean protein you can handle, plus 1.5 tablespoons of oat bran and at least 6 cups of water daily. In the â Cruiseâ phase (which can last several months), you add unlimited amounts of non-starchy veggies every other day, plus an extra half-tablespoon of oat bran. When you get to the third stage, â Consolidationâ (5 days for every pound you've lost), you can have veggies every day, plus one piece of fruit, 2 slices of whole-grain bread, and 1 serving of hard cheese. During this phase, you can also have 1 or 2 servings of starchy foods and 1 or 2 âcelebrationâ meals where you can eat whatever you want. The final phase, â Stabilizationâ (ongoing), is all about maintenance. You can eat whatever you like, except for one day a week when you follow the all-protein rules from the diet's â Attackâ phase. In this phase, you also eat 3 tablespoons of oat bran a day and walk 20 minutes every day. Sugar-free gum, artificial sweeteners, spices, and unsweetened coffee and tea are allowed. As for alcohol, you can have a glass of wine per day during the consolidation and stabilization phases. Prepping your food shouldn't be a problem, and you don't need exotic ingredients. But you will be pretty restricted in what you can eat at the start of the diet. Level of limitations: Eating mainly protein and oat bran can get tiresome. Cooking and shopping: It's easy to plan, shop for, and prepare meals on this diet. Packaged foods or meals: None required. In-person meetings: No. Exercise: A daily 20-minute walk is essential to the plan. Vegetarian or vegan: This diet is based on eating a lot of lean meat, poultry, fish, shellfish, fat-free dairy, and eggs. Seitan, tempeh, and tofu are the veggie protein options available -- beans, nuts, and lentils aren't on the diet's list of allowed foods. On days when all you eat is protein (no fruits or veggies allowed), things can get boring quickly if you don't eat meat. Low-fat diet: If you're already following a low-fat regimen or have a heart condition that requires eating ultra-low-fat foods, this diet might fit like a glovework, since the allowed foods -- mainly protein, veggies, and fruit -- are lean, low-fat, or no-fat. Gluten-free: The earlier phases of the diet may work for a gluten-free diet, but as the rules relax, it's not strictly gluten-free. If you're trying to avoid gluten completely, make it a habit to read food labels carefully. Costs: None beyond your shopping, unless you sign up for online coaching, which is optional and costs $29.99 per month. Support: There is a strong community aspect to this plan. The official web site offers sample recipes, inspirational success stories from real men and women (not just superstars), and coaches who help guide dieters through each phase. Does It Work? The first stages of this diet will likely result in significant weight loss due to the few carbohydrates allowed on the plan. But when you go back to eating normally after reaching your goal weight, you may gain some of this weight back. Research shows high-protein diets are effective for weight loss, but experts still do not know what the long-term effects are for your health and weight. And there is no evidence that having one all-protein day, along with exercise, is enough to maintain your weight loss. Is It Good for Certain Conditions? Although the diet can lead to weight loss, which can help with certain health conditions, the risks may outweigh the benefits. If you're on medication for diabetes, you will likely need to change your dose, because the first two stages are very low in carbohydrates. If you have renal disease, you might get more protein than your kidneys can handle. And if you have heart disease or a digestive disorder, you would be missing out on heart-healthy fiber. Because of the restrictive nature of this plan, it's important to check with your doctor first if you have a health condition. The Final Word Unlike other high-protein diets, this plan focuses on lean protein sources over those high in saturated fat. And protein can make you feel fuller longer, helping you lose weight. The downside is that this plan doesn't teach lifelong healthy eating habits. Even more problematic, it recommends that you stay in the consolidation phase until you reach your goal. If you have a lot of weight to lose, this phase could go on for months or even years, which could lead to a nutritionally inadequate diet. If you're looking to lose a relatively small amount of weight fast, then this diet may work for you. If you are over 50 or have a condition, like diabetes, or need to lose a lot of weight, talk to your doctor first.