Diet Plans & Programs: The "Skinny" on Popular Diet Plans
The Atkins Diet
The Diet Plan Theory
The Atkins diet may be one of the most well-known fad diets. It is a high-protein, high-fat, low-carbohydrate plan. This diet has been around for decades and has undergone many revisions. The previous plan allowed for unrestricted amounts of meat, cheese, and eggs while severely restricting carbohydrates, including sugar, bread, pasta, milk, fruits, and vegetables.
The Atkins diet web site states the current plan "is about eating delicious and healthy foods, which makes it so much better than any of those fad diets out there. You eat a variety of your favorite foods -- lean protein, leafy greens, vegetables, nuts, fruits, whole grains. Plus, you get delicious Atkins bars and shakes from day one and every step of the way."
The plan is based on the theory that eating carbohydrates creates a production of insulin, a hormone secreted from the pancreas, leading to increased weight gain and hunger. When converting to this approach, the plan holds that dieters will experience a reduced appetite, and their bodies will use stored fat for energy versus burning glucose from carbohydrate digestion. Burning fat for energy will supposedly lead to weight loss.
The most recent version of the Atkins diet is by far the most nutritionally balanced. For the first time, the Atkins diet has placed an emphasis on the kinds of fat being consumed instead of allowing all dietary fats. The monounsaturated and polyunsaturated fats are now emphasized over saturated and trans fats. The diet has also changed to allow "good carbs" instead of severely restricting all carbohydrates. These foods provide fiber, vitamins, and minerals that were once lacking in this diet. The high amount of protein will be beneficial in keeping you full. Research is clear that protein has a positive impact on increasing satiety, which means that you will feel full between meals.
The Atkins diet has gone through numerous revisions over the years, though there was never any acknowledgement of flaws in any of the diet plans. Until recently, there have not been any studies on the safety or efficacy of the Atkins diet. Short-term studies have shown improvements in blood cholesterol and blood sugar and an increased weight loss over the first three to six months in comparison to control diets. Unfortunately, the weight loss is not sustained at one year, and the improvements that were seen were due to weight loss and not the actual diet. The long-term safety of low-carbohydrate, high-protein diets is unknown at this time. In a 2007 rating of diet books done by Consumer Reports, the Atkins diet was ranked at the bottom.
There are four phases to the plan, and the first one is severely restricted in carbohydrates. The induction phase lasts two weeks, and the claim is you can lose up to 15 pounds in this time. During this time you consume no more than 20 grams of carbohydrates per day. For example, one slice of bread has 15 grams of carbohydrates, one serving of fruit has 15 grams of carbohydrates, one serving of dairy has 12 grams of carbohydrates, and one serving of vegetables can have between 5 and 15 grams of carbohydrates. It's clear that 20 grams is extremely limited, potentially unhealthy, and would be very difficult to follow for the long-term.
The Atkins web site states that "depending on how much weight you have to lose, you can safely continue with the induction phase as long as the following three conditions are met:
- Your blood chemistries, lipid values, blood pressure or blood sugar levels continue to improve or remain stable and within normal limits. (You will have to visit your doctor to have these levels tested.)
- You feel well and are experiencing a high energy level, normal sleep patterns, and stable moods.
- You are not bored. Boredom could lead to cheating and undermine your efforts."
Most people who follow this diet are not under medical supervision, and this can become a very dangerous situation for them.
The the induction phase gets people used to losing weight at a fast rate, which will not last and is not healthy. Faster weight loss does not mean healthy weight loss. Any diet that emphasizes fast, easy weight loss is one to approach with caution. The guidelines are clear that a safe, healthy rate of weight loss is to lose 1 to 2 pounds per week after the first couple of weeks. The Atkins diet states you will lose "only body fat" by eating regular meals, taking in adequate calories, and keeping your insulin levels down. There is no way to only lose body fat when losing weight. Each pound you gain from consuming excess calories is 75% fat and 25% muscle, and each pound you lose from cutting back 3,500 calories is the same ratio of fat and muscle. Claims that you will lose only fat are not based on science despite the fact that the Atkins diet claims to be scientifically based.
The Pritikin Principle
The Diet Plan TheoryThe Pritikin diet is a very low-fat, high-carbohydrate eating plan. The focus is to eat vegetables, fruits, and high-fiber grains. Fats should not exceed 10% of total daily calories. Nathan Pritikin's diet is based on the theory of eating low-fat, low-calorie, plant-based foods to promote weight loss and improve or prevent heart disease. The revised Pritikin diet includes a "Calorie Density Solution:" Consume low-calorie dense foods (for example, apples, brown rice) until full, six to seven times daily. Eating low-calorie foods throughout the day will reduce hunger and cause weight loss.
AdvantagesResearch has shown that the calorie density of our diets will impact our weight. The calorie density is the amount of calories in a given weight of food. Consuming foods that are considered low-calorie dense aids in weight loss. These foods will provide a high volume without a lot of calories. By replacing foods that are considered high-calorie dense, you save additional calories. Some find it more satisfying to focus on consuming low-calorie dense foods in large quantities versus counting calories. The Pritikin diet also encourages daily exercise and stress-reduction techniques.
DisadvantagesThe most controversial part of this diet is the severe fat restriction. The American Heart Association recommends a diet with 25% to 35% of your calories from fat. The Pritikin Principle requires you consume less than 10% of your calories from fat. Besides providing taste to your diet, dietary fat has other functions, and 10% may be too low to meet your needs. There has been a considerable amount of research showing the health benefits of omega-3 fats, including protecting your heart. The American Heart Association now recommends that people without coronary heart disease eat a variety of omega-3 fat-containing fish at least twice a week and that those with coronary heart disease consume one gram of omega-3 fats per day. Dietary fat is also needed to transport the fat-soluble vitamins A, D, E, and K. Without fat to transport them, they will not be able to serve their functions in your body. Our diets are meant to have a balance of protein, carbohydrates, and fat. When you consume too little of one of these nutrients it means you are consuming too much of another nutrient. Most people who follow a very low-fat diet end up consuming an excess amount of carbohydrates. Too much of any nutrient can cause health problems. The Dietary Reference Intake (DRI) established the need for each one of these nutrients based on research for optimal health and weight. The DRI set the dietary goals at 45% to 65% from carbohydrates, 20% to 35% from fat, and 10% to 35% from protein. If you follow the Pritikin Principle it would be best to adjust your intake to meet the DRI guidelines.
The Zone Diet
The Diet Plan Theory
The Zone diet is a high-protein, low-carbohydrate, fat-controlled eating plan. It is not as restrictive as other high-protein diets and it allows for a broad range of foods to be consumed. A small amount of protein is combined with twice the amount of "favorable" carbohydrates, including fruits and vegetables. If choosing "less desirable" carbohydrates, the portion size is smaller. Sears' Zone diet is based on the theory that the human body is genetically programmed to reach peak efficiency when all meals, including snacks, consist of a set caloric ratio of carbohydrates, proteins, and fats. The diet recommends an intake of 40% of calories from carbohydrates, 30% from protein, and 30% from fats (40-30-30). When this ratio is achieved, the body is working within the "zone." The body will have maximum energy and weight loss.
The Zone diet promotes eating a balance of each nutrient, without severely restricting calories. Protein increases your feeling of fullness, helping you to avoid eating between meals, and there is a guide to what kind of fat you can consume. Healthy fats are encouraged in place of the saturated and trans fats. The calorie restriction will help you lose weight.
The claims made about the health implications of carbohydrates and protein are controversial. As with other fad diets, one nutrient is being made to look like the enemy (carbohydrates), while protein is made to look like the key to weight loss and health. Most diets that are against carbohydrates use the arguments that we consume less fat and more carbohydrates than we did 10 years ago, and obesity is on the rise. This is half true. We consume more carbohydrates, which means we consume more calories. Our fat intake remains above the recommendations, but the percent of our total calories from fat has come down because we are now consuming more calories. Again, research clearly shows that a balance of each of these nutrients is needed and that an excess or deficiency in any of them will cause problems. This diet can be difficult to stick with long-term, so weight regain can be an issue.