Results

Weight loss
The Atkins Diet says that you can lose 15 pounds (6.8 kilograms) in the first two weeks of phase 1 — but it also acknowledges that those aren't typical results. It says that you'll continue to lose weight in phases 2 and 3 as long as you don't eat more carbs than your body can tolerate.

Most people can lose weight on almost any diet plan that restricts calories — at least in the short term. Over the long term, though, studies show that low-carb diets like Atkins are no more effective for weight loss than are standard high-carbohydrate diets and that most people regain the weight they lost regardless of diet plan. However, studies have shown that people who continued to follow diet plans such as Atkins for two years did lose an average of nearly 9 pounds (4.1 kilograms) overall. Some studies suggest that it's not cutting carbs that leads to weight loss with Atkins. Instead, you may shed pounds because your food choices are limited and you eat less since the extra protein and fat keep you feeling full longer.

The bottom line is that to lose weight you must reduce the calories you take in and increase the calories you burn. Traditional recommendations for weight loss advise losing 1 to 2 pounds (0.45 to 0.9 kilograms) a week by reducing calories and fat and emphasizing complex carbohydrates. Losing a large amount of weight rapidly could indicate that you're losing water weight or lean tissue, rather than fat. The Atkins Diet acknowledges that you may initially lose water weight. In some situations, fast weight loss can be safe if it's done in a healthy way. For example, doctors may prescribe a medically supervised very low calorie diet for rapid weight loss if you're obese or have serious health problems. In addition, some diets include an initiation phase to help you jump-start your weight loss, including the Mayo Clinic Diet.

Physical activity and exercise help you burn more calories, aiding weight loss. Regular physical activity is also vital to prevent regaining the weight you've lost and, of course, provides numerous health benefits. Although the Atkins Diet says exercise is important, it doesn't specify how much you need. It defers to Department of Health and Human Services guidelines, which recommend getting at least 150 minutes a week of moderate aerobic activity or 75 minutes a week of vigorous aerobic activity.

Health benefits
The Atkins Diet says that its eating plan can prevent or improve serious health conditions, such as metabolic syndrome, diabetes, high blood pressure and cardiovascular disease. In fact, almost any diet that helps you shed excess weight can reduce or even reverse risks factors for cardiovascular disease and diabetes. And most weight-loss diets — not just low-carb diets — may improve blood cholesterol or blood sugar levels, at least temporarily. One study showed that people who followed Atkins had improved triglycerides, suggesting better heart health. But there have been no major studies to show whether such benefits hold up for the long term or increase how long you live.

Some health experts believe that eating a large amount of fat and protein from animal sources, as allowed on the Atkins Diet, can increase your risk of heart disease or some cancers. However, it's not known what risks, if any, the Atkins Diet may pose over the long term because most of the studies about it have lasted for a year or less.

Risks

The Atkins Diet acknowledges that drastically cutting carbs in the early phase of the program can result in some side effects, including:

  • Headache
  • Dizziness
  • Weakness
  • Fatigue
  • Constipation

In addition, some low-carb or very low carb diets restrict carbohydrates so much that they result in nutritional deficiencies or insufficient fiber, which can cause such health problems as constipation, diarrhea and nausea. Eating carbs that are high fiber, whole grain and nutrient dense can improve the health profile of programs like the Atkins Diet, though. In addition, the Atkins Diet has changed over time to help prevent health problems, and it now recommends taking a small amount of extra salt, along with vitamins or supplements.

It's also possible that restricting carbohydrates to less than 20 grams a day — the recommendation for phase 1 of the Atkins Diet — can result in ketosis. Ketosis occurs when you don't have enough sugar (glucose) for energy, so your body breaks down stored fat, causing ketones to build up in your body. Side effects from ketosis can include nausea, headache, mental fatigue and bad breath.

In addition, the Atkins Diet isn't appropriate for everyone. For example, Atkins warns that people with severe kidney disease should not follow the diet. It also cautions that the weight-loss phases of the diet aren't suitable for women who are pregnant or breast feeding. The Atkins Diet recommends that you consult your doctor before starting the diet, especially if you have diabetes or gout or take diuretics, insulin or oral diabetes medications.

Jul. 07, 2011 See more In-depth