- Keto Diet
- Atkins Diet
- Pritikin Principle
- Zone Diet
- South Beach Diet
- Ornish Diet
- Jenny Craig
- Weight Watchers
Weight loss seems simple
A calorie is a calorie, the advice goes. Eat too many ... gain weight. Eat fewer ... lose weight. But many believe weight loss is more than a calorie equation, with so-called new-and-improved ways to lose weight being ever popular. Americans spend an estimated $42 billion annually on weight loss foods, products, and services. With that much money at stake, it's no surprise there are an overwhelming number of "fad" diets and other weight-loss products on the market.
Having so many diet options makes it difficult to know which ones to trust. For this reason, The Partnership for Healthy Weight Management has developed the "Voluntary Guidelines for Providers of Weight Loss Products or Services." The mission for these guidelines is to "promote sound guidance to the general public on strategies for achieving and maintaining a healthy weight." According to the guidelines, effective weight management involves:
Behavior modification that includes:
- Dietary intervention
- Healthful eating in accordance with the Dietary Guidelines for Americans
- A reduction in calories
- A lowered fat consumption
- An increase in fruit, vegetable, and whole grain consumption
- Physical activity
- Increased frequency
- At least moderate intensity
Medical, pharmacological, and surgical intervention:
- May be necessary for people with more serious cases of overweight and obesity
- Have to be used in conjunction with behavior, diet, and physical activity modifications
It is important to look for a plan that includes strategies for maintaining weight loss. There is nothing worse than regaining the weight that took you an enormous amount of hard work and patience to lose.
Most popular diets are considered fad diets. There is no clear definition for what constitutes a fad diet. Merriam-Webster defines a fad as "a practice or interest followed for a time with exaggerated zeal." Fad diets often promise quick results with a short time commitment. Long-term success requires permanent changes in behavior, diet, and activity.
Ways to spot a fad diet:
- It claims fast weight loss
- Claims that sound too good to be true
- Foods defined as "good" and "bad"
- Less than 1,000 calories daily
- A required vitamin/mineral supplement or food product
- Elimination of a major food group (grains, fats, meats, dairy, fruit, vegetables)
- Lack of long-term randomized scientific studies proving the diet works and is safe. A randomized study distributes participants in a deliberately random way into either the non-tested diet group or the special diet group. Some fad diets state there is research to support their claims, but the research is only done with a few people or does not exist.
- Elimination of an essential nutrient (carbohydrates, fats, proteins)
- No activity or exercise needed
- It's written by someone with no expertise in weight management
The following review examines the advantages and disadvantages of several popular diet plans. Many of the diets emphasize the restriction of one nutrient as the basis for their plan. The other food groups and nutrients are allowed in limited or unlimited quantities, depending on the plan. Weight loss is impossible without a calorie restriction, so each diet has to provide fewer calories than your body needs to maintain your weight. Any diet that claims otherwise can end up causing weight gain. Various diet plans are summarized below to help you learn to review them for safety and effectiveness.
The Keto Diet
The Keto Diet Theory
The ketogenic or keto diet is a low-carb, high-fat diet that involves drastically restricting carbs and replacing them with fats. Reducing carbs and depriving the body of glucose leads to ketosis, a metabolic state in which the body breaks down stored fat into ketones for energy instead of glucose. The keto diet has therefore gained attention for its ability to promote quick weight loss in some people.
A typical keto diet may be 70% fat, 20% protein, and 10% carbs, although this ratio of nutrients varies. All variations of the diet, however, involve reducing carbs, increasing fat, and including a moderate amount of protein. The diet requires eliminating all refined and unrefined carbs, even nutritious sources such as whole grains and some fruits.
The ketogenic diet was originally developed as a form of therapy for epilepsy, because studies showed that the keto diet could be effective in treating seizure disorders that do not respond to two mainline anti-seizure medications. While the reasons for this are unknown, researchers believe that the diet induces metabolic changes that may help lower the risk of seizures.
Proponents of the keto diet argue for its use in weight control and believe that the diet may increase satiety and decrease the levels of hunger-stimulating hormones, leading to fat loss. In some cases, following the keto diet in the short term may also lead to lower blood cholesterol levels, blood pressure, and blood sugar, although these benefits can be obtained by following other traditional weight loss programs. Physicians do not typically recommend a keto diet because the same benefits can be obtained from safer weight loss plans.
Since the keto diet severely restricts foods that contain important nutrients, nutritional deficiencies are a risk factor. Short-term health risks include flu-like symptoms, bad breath, constipation, irritability, and trouble sleeping. Long-term health risks include liver disease, heart damage, kidney stones, gout, and osteoporosis.
The Atkins Diet
(Robert C. Atkins, M.D.)
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 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
(Created by Nathan Pritikin, Revised by Robert Pritikin)
The Diet Plan Theory
The 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.
Research 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.
The 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
(Barry Sears, Ph.D.)
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.
The South Beach Diet
(Arthur Agatston, MD)
The Diet Plan Theory
The South Beach diet is the newest high-protein, low carbohydrate, and fat-controlled diet. This diet claims that the cause for obesity "is simple: The faster the sugars and the starches you eat are processed and absorbed into your bloodstream, the fatter you get." The goal is to "take out bad fats and bad carbohydrates." Like many of the fad diets, it is divided into different phases. The first phase claims to eliminate cravings and kick-start weight loss; the second phase is for long-term, steady weight loss; and the third phase is to be followed for 365 days a year once you have achieved your weight loss goal.
The second and third phases of this diet promote a balanced diet that can be beneficial to your health and weight. These phases promote consistent meal times, healthy snacks and desserts, and water. The meal plans and recipes can be useful for those who need some guidance on what to eat. There are now six other books and an interactive web site supporting this plan.
The theory behind the diet is not the reason you will lose weight if you follow this plan. Weight loss can only occur when you consume fewer calories than your body needs. In the introduction chapter the author makes numerous claims that you do not need to limit the quantity of food that you consume and then provides portion restrictions on many high calorie foods, such as nuts. It's appealing to hear you can eat unlimited quantities, but weight loss will not be achieved without limitations.
The initial phase of this diet should be avoided. This two-week phase claims to produce a weight loss of eight to 13 pounds with severe dietary restrictions; including fruit, dairy, and starches. Phases like this are usually included so people see quick results, but are limited in time because they are not nutritionally balanced and can't be followed for a long period. It tends to be more discouraging than motivating to lose quickly and to feel like you are "on a diet." Long-term weight loss and maintenance takes time, patience, and a lot of hard work. It's best to begin slowly and to always consume a nutritionally balanced diet.
Eat more, weigh less: The Ornish Diet
(Dean Ornish, MD)
The Diet Plan Theory
Eat More, Weigh Less is one of the few diets developed as a result of research. The primary goal of this diet was to reverse heart disease. The basis for this diet is to consume a high-fiber, low-fat, vegetarian diet with limited amounts of dairy foods. The goal is to consume primarily complex carbohydrates (vegetables, fruit, and whole grains), low total fat primarily from omega-3 fatty acids and limited in saturated fat, and low sugar. Physical activity and stress management are also emphasized.
The research does support the health benefits of this diet, and you will lose weight if you stick with the plan. The web site provides recipes and detailed information on nutrition, exercise, and stress management.
The primary con to this diet is that it can be extremely limited and difficult for some people to follow. The average fat intake is only 6% of your total calories, which is considerably lower than the recommended 20% to 35%. This limitation is because meat is omitted from the plan. Cutting out an entire food group may be too much of a restriction to maintain over the long-term, so some people do best by modifying this diet to allow for a moderate amount of meat. The high fiber intake may also pose a problem initially. It's best to slowly increase the amount of fiber you consume so your body can get used to it. The goal is always long-term weight loss and maintenance. This diet does have the research to support it, but it may need modifications to make it work for you.
The Diet Plan Theory
Jenny Craig has become best-known for the celebrities who are followed while losing weight on this diet. They explain how easy it is and how delicious the food is, and you see the results as they are happening. This diet provides you with your foods and snacks to ensure you consume the exact amount of calories your body needs to lose weight. You add fresh produce and dairy. You meet with a consultant on a weekly basis to discuss your progress, and who will assist you with transitioning to your own food when you are ready to do so. Physical activity is emphasized throughout the diet.
The primary advantage to this diet is that you will lose weight if you eat what you are given. Portion-and-calorie-controlled meals are great tools for long-term weight loss and maintenance. They take away the guesswork of how many calories you consume, they can be nutritionally balanced, they are quick and easy to prepare, and they teach you about healthy portion sizes.
As with all diets, nothing works for everyone, and nothing works forever. The celebrity endorsements are great when they work, but the celebrities who regain their weight once they discontinue this plan are proving that this is not the answer for everyone. Many people prefer to be able to eat food they prepare and do not like the idea of prepackaged foods.
The consultants are not professionals in this field. They undergo a training course but are not trained therapists, registered dietitians, or exercise physiologists, so the advice and support that you receive will be limited to what they have been taught to say. If you are taking any medications or have any health conditions, it is best to work with trained professionals.
The Diet Plan Theory
The NutriSystem Advanced diet is a low glycemic index, high-fiber, and high-protein diet. The prepackaged food is provided for you by ordering online or by calling the toll free number. The plans are: Women's, Men's, Women's Silver, Men's Silver, Women's Type II Diabetic, Men's Type II Diabetic, or Vegetarian. An exercise DVD is included along with a Mindset Makeover behavior modification guide.
This diet does address the three necessary components for successful weight loss and maintenance; diet, physical activity, and behavior. Prepackaged foods can be an effective tool for weight loss. You will be provided with the appropriate number of calories for weight loss without having to worry about counting anything. You add fresh produce and dairy. This will give you the opportunity to learn what appropriate portion sizes are and which foods are necessary for a well-balanced diet based on your specific needs. The variety of programs based on gender, age, health, and dietary preference is another positive component of this diet.
The Mindset Makeover was developed by one of the leading psychologists in the weight loss field, Gary Foster, Ph.D. It is designed to "help people learn new behaviors when it comes to weight loss and related lifestyle issues." This behavior piece is essential but very rare in most diets. You are given access to this and an online account with community support as part of each of the programs.
Prepackaged foods are not for everyone and typically not something to use forever. They can be very limiting and create the sense of being "on a diet." They will also get in the way of social events in which food is involved. Most people find that they only want to use this type of a diet for the short-term or for one or two meals per day. The other negative aspect of this diet is that the prepackaged foods contain the artificial sweeteners Sucralose and Acesulfame K.
The dietary focus on this diet also has some limitations. The idea of "good carbs" and "bad carbs" is controversial. While there is some truth to the role of glycemic index in hunger, it is not a guaranteed tool for weight management. Labeling foods as "good" and "bad" creates problems for people trying to develop healthy eating habits. A well-balanced diet requires whole wheat sources of starch, while allowing for some sugar.
The Diet Plan Theory
Weight Watchers has been around for many years. There have been changes to the program, but weekly meetings have remained a part of the plan. You can attend meetings in person and/or use online support when you are a Weight Watchers member.
The two diet options that are currently available are the Flex Plan and the Core Plan. The Flex Plan is an updated version of the POINTS Food System in which the goal is to stay within your recommended amount of points each day. The POINTS value for foods is calculated based on the food's calories, fat, and fiber. Along with your weekly POINTS target you are also given a "Weekly Allowance" to use for indulging or special occasions.
The Core Plan is based on the science of energy density. Energy density refers to the amount of calories in a given weight of food. Foods that are considered low energy dense foods have a small amount of calories for a large volume of food (for example, vegetable soups, vegetables, and fruit). High energy dense foods provide a lot of calories for a small amount of food (for example, oils, butter, cream sauce). The Core Plan provides a "balanced diet by centering on a list of healthy foods that keep you full longer."
The support and information provided online and in-person sets Weight Watchers apart from most diets out there. There are numerous meetings across the country to choose from. For many people, having a place to weigh-in each week is a key to success.
The focus on a balanced diet, exercise, and behavior changes is another advantage to this diet. The goal is to educate people on all three components and assist with both weight loss and maintenance. The two plans give people an option to find what works best for their own success.
Many people have a "been there, done that" attitude when it comes to Weight Watchers. They have tried it, may have had some success, may have even gone back a couple of times, but end up feeling that it can't help them any longer. The group leaders at the meetings are not trained experts; they are former members who have had success with Weight Watchers. When someone is not having success the options for what to do can be greatly limited by the lack of experience and knowledge of the leader. There is a strong emphasis on weighing in each week. Many people have a difficult time attending a meeting when they are not having success. However, most people will not lose weight every single week, so expecting to do so is a recipe for failure. The time when people need the support the most is when they are not losing, but most meetings are not set to address this.
While there are two diet options, this still may not be enough for everyone. If counting points and following a low-energy dense diet do not work for you, there is no other option left. The best weight loss diet is one that fits your lifestyle and needs, and you can't always get that with this plan.
Lose Weight, and Keep It Off
It is indisputable that as a country we are more overweight and obese than we have ever been. As a result, the diet industry has grown along with us. Some diets genuinely try to help people lose weight and keep it off, while others look to make money by saying whatever it takes to get people to believe their claims.
You need to be an educated consumer when it comes to weight loss. It's not enough to see that a doctor is the author of a book. You need to digest what is being said, and look for the facts supporting the claims. It takes modifications in behavior, diet, and activity to succeed at weight loss. It also takes time, patience, commitment, and lots of hard work. There will never be one diet that is the "cure" for everyone. If you are having difficulties with weight loss, seek help from your physician. Dieting is a complex issue and ongoing professional support may be needed for success. It is possible to lose weight and keep it off, so never give up hope. Instead, find what works best for you right now, and be open to change as you go along.
Health Solutions From Our Sponsors
Consumer Reports; "Improving Americans' Health Literacy," The American Dietetic Association, 2005; "U.S. Diet Guide Puts Emphasis on Weight Loss," The New York Times.
Previous contributing author: Pamela Cekola, R.D.