Diet Plan Evaluations
Get the Skinny on the Zone Diet
High carbohydrate diets make athletes fat and impair performance. Sounds hard to believe? It is. Yet, that's what Barry Sears, Ph.D., claims in his hot- selling book, Enter the Zone. Sears promises that you can "lose weight permanently" by following "exceptionally easy" rules. In the process you can also reach a near-euphoric state of maximum physical and psychological performance. In case these benefits aren't enough, Enter the Zone also claims that the Zone diet can treat heart disease, cancer, diabetes, and even AIDS.
What's the bottom line here? Does a high carbohydrate athletic diet make you fat and hurt your performance? Has Sears found a better way to eat? No.
As a registered dietitian, exercise physiologist, and endurance athlete with over 16 years of experience studying and practicing performance nutrition, I'll tell you why.
Enter the Zone maintains that carbohydrates are bad because they raise your blood sugar level and cause the release of the hormone insulin -- a supposed monster hormone. Actually, insulin is an essential hormone that helps transfer sugar or glucose from the bloodstream to the body's cells, where it's used to fuel all of our activities. However, Enter the Zone claims that when insulin levels go up, "you're stuck in carbohydrate hell" and way out of the Zone -- the "state in which your body and mind work together at their ultimate best."
According to Sears, the problem is that insulin causes the body to make "bad" eicosanoids -- hormone-like substances that the body makes from certain unsaturated fatty acids. Enter the Zone claims that "bad" eicosanoids cause most major health problems, such as heart disease, cancer, arthritis, and even depression. "Bad" eicosanoids also supposedly harm your performance by reducing oxygen transfer to the cells, lowering blood glucose levels, and interfering with body fat usage.
Reality Check Number One -- eicosanoids don't cause disease or impair athletic performance. The claim that eicosanoids are all-powerful is ridiculous -- the body's physiology just isn't that simple. There's also no evidence that insulin even makes "bad" eicosanoids.
According to Sears, insulin not only hurts your health and performance, it makes it hard for you to stay, or become, thin. Basically, Enter the Zone treats insulin as the hormone that makes you fat. Supposedly, insulin does this by taking your high-carbohydrate food and storing it as fat rather than allowing the body to use it for energy.
Reality Check Number Two -- insulin doesn't make you fat.
Like it or not, what you weigh depends on how many calories you take in compared to how many you burn off. Eating a high percentage of calories from carbohydrate doesn't make you fat -- you must eat too many calories relative to your needs for insulin to lay down fat. However, your body would rather burn carbohydrate for energy than store it as fat.
Unfortunately, not paying attention to calories gets alot of people into trouble. When health professionals encourage people to eat more carbohydrate and less fat, many folks get the wrong idea. They think they can eat as much high-carbohydrate food as desired, as long as the food is fat-free. The result -- these people can't lose weight or even gain weight because they eat too many calories in the form of high-carbohydrate, low-fat sweets as well as extra large portions of starches such as bread and pasta. Instead of blaming their forks, they blame the carbohydrate.
The Moral of This Story -- active people can't eat an unlimited amount of carbohydrate by cutting down on their fat intake. Cutting back on dietary fat does reduce total calories more than cutting back on dietary carbohydrate, because fat supplies more than twice the calories by weight. Fat is also more likely to be stored as body fat than is carbohydrate. However, if you cut back on fat calories but add them back in the form of carbohydrate calories, you're not going to lose weight. It's a simple matter of energy balance whether you're an athlete or a couch potato.
Even though carbohydrate and insulin are not villains, Enter the Zone recommends a complicated, carbohydrate-restricted diet. The book tells you to treat food as a drug, to "eat food in a controlled fashion and in the proper proportions, as if it were an intravenous drip." Specifically, that means eating exactly 40% of calories as carbohydrate, 30% as protein, and 30% as fat at each meal and snack. Supposedly, this revolutionary diet will make you thinner, healthier, and a better athlete. What it really does it take the fun out of eating. Almost all professional health groups in the country recommend 55 to 60% calories as carbohydrate, 10-15% as protein, and the remainder as fat. And not every time you sit down to eat.
Reality Check Number Three -- there's nothing magical about why the Zone diet promotes weight loss -- it's simply an extremely low-calorie diet.
Enter the Zone attempts to disguise this fact by having you count fancy protein and carbohydrate blocks instead of calories. Although the book says "don't focus on calories," the Zone diet provides only 800-1,200 calories a day for the average person.
You'll lose weight on the Zone diet because of the severe caloric restriction -- not because of what is supposedly happening to your insulin levels or eicosanoids. You'll lose something else, too, eventually. Your performance. You can't train or compete well for very long on such a low calorie, low- carbohydrate diet. You need to eat enough calories and carbohydrate to maintain your muscle glycogen levels -- the favored fuel for exercise. The Zone diet supplies about half the number of calories I recommend for an active person trying to lose weight. Follow this diet and the only zone you'll enter is the twilight zone of near starvation and impaired performance.
Contrary to what Enter the Zone claims, eating a high carbohydrate meal one to four hours before exercise improves performance by "topping off" your glycogen stores. Consuming carbohydrate during workouts lasting longer than an hour aids endurance by providing glucose for your muscles to use when they're running out of glycogen. And, taking in carbohydrate right after hard training increases muscle glycogen storage and helps improve your recovery time.
No dietary regimen can change your body's preference for carbohydrates over fats as fuel or help you burn more fat. Carbohydrate, not fat, is the preferred fuel for exercise at or above 70% of aerobic capacity -- the intensity at which most people train and compete. And, as far gradual loss of body fat, that comes from burning more calories during exercise than you take in, not from some special dietary ratio.
The Bottom Line -- you don't need to follow this rigid diet for weight loss, optimum performance, or health.
Get the Skinny on Sugar Busters
The Hype:
"Cut sugar to trim fat, lose weight, lower your cholesterol, achieve optimal wellness, increase your energy, help treat diabetes and other diseases."
How it Works:
The authors' basic premise is that sugar is poison to our bodies. I wonder how any of us manage to live, especially after Halloween, Easter or Valentine's Day. They don't just list refined sugars such as corn syrup, molasses or honey as toxic. They also include high-carbohydrate foods such as potatoes, corn, white rice, white pasta, carrots, white bread products and beets. Along with other books in the high-protein, low-carbohydrate diet craze, the authors conclude that foods high in carbohydrates cause our bodies to overproduce insulin, thus causing obesity.
Fact or Fiction?
Once again, fiction. There is no evidence that sugar in itself is toxic. In fact, the only health reason to limit sugar intake is to prevent dental cavities. In addition, foods high in carbohydrates (potatoes, corn, bread and so on) don't by themselves cause obesity. Eating too many calories, no matter the food source, is the cause of weight gain. The premise that high-carbohydrate foods cause overproduction of insulin is also false. Obesity, not a single factor such as carbohydrates, causes overproduction of insulin. The USDA Food Guide Pyramid and others recommend more grains and vegetables in our diet, the opposite of Sugar Busters!
Our Advice:
Don't waste your money on this book. Although I strongly favor eating less refined sugar in foods such as cookies, cakes and many reduced-fat foods such as cereal bars, I certainly can't recommend eating less food high in carbohydrates. Some of the recipes in the Sugar Busters! book have 41 percent to 85 percent of their calories from fat, far above today's health guidelines of 30 percent. You may lose weight on this diet (some of the menus provide only 1,250-1,350 total calories -- far too few for most of us), but only in the short term and most certainly at the risk of vitamin and mineral deficiency.
Here are some interesting guidelines from a group called the Food and Nutrition Science Alliance, made up of the American Dietetic Association, the American Society for Clinical Nutrition, the American Society for Nutritional Sciences and the Institute of Food Technologists.
The 10 Red Flags of Junk Science
1. Recommendations that promise a quick fix.
2. Dire warnings of danger from a single product or regimen.
3. Claims that sound too good to be true.
4. Simplistic conclusions drawn from a complex study.
5. Recommendations based on a single study.
6. Dramatic statements that are refuted by reputable scientific organizations.
7. Lists of "good" and "bad" foods.
8. Recommendations made to help sell a product.
9. Recommendations based on studies published without peer review.
10. Recommendations from studies that ignore differences among individuals or groups.
Get the Skinny on Jenny Craig
The Hype:
According to their Website, Jenny Craig Lifestyle Weight Management is "about learning how to manage your weight one simple change at a time." The company, which has 781 centers, says that it promotes a long-term focus on weight management that includes personal support, nutrition, exercise and lifestyle changes.
How It Works:
Jenny Craig started in 1983 by providing frozen meals to its clients as a means of food management. Personal weekly consultations for motivation and behavior change are another company hallmark. They have since branched out into cookbooks and programs that encourage clients to make food choices from readily available foods they and their families usually eat. They have also begun an at-home program for people who do not live close to an established center. Food is shipped to your doorstep by UPS, and personal consultations are conducted over the phone.
Fact or Fiction?
Jenny Craig program materials cover all areas health professionals recommend in weight-loss programs:
· sound nutrition advice
· recommendations for an active lifestyle
· focus on small behavior changes for gradual weight loss
· emphasis on long-term weight maintenance instead of short-term weight loss
However, their advertisements show people who have lost large amounts of weight quickly, followed of course by a disclaimer that these "results are not typical."
The Skinny:
If you want to participate in an established program where you will receive one-on-one support and education, Jenny Craig may be the choice for you. Before you commit to any program, make sure you understand all the fees and the services provided. And unless you plan on eating their frozen foods for the rest of your life, take advantage of the version of their program that allows you the flexibility of making your own food choices.
Get the Skinny on Herbalife Weight Loss Systems
The Hype:
If you want to lose weight without changing your eating habits, exercising, or doing anything more difficult than swallowing some capsules and eating a meal replacement beverage twice each day, then, Herbalife claims, they have the plan for you. However, their system is unproven and contains potentially dangerous supplements. Their slogan "Enhancing your quality of life through good nutrition" may sound like they have your best interests at heart, but many health experts think the company is more concerned with making money than promoting good health.
How It Works:
Herbalife promotes a variety of products, from weight loss pills to colon cleansers to herbal shampoos, through a multi-level marketing system. Their weight loss system, Thermojetics, includes the use of a protein drink to replace two meals with a balanced third meal. You are also encouraged to take a variety of vitamins, minerals, and herbal supplements. The total calories from the program are approximately 1000 per day, lower than recommended for good health. The company literature promotes the herbal supplements as a way to increase energy as well as increase your body's absorption of vitamins and minerals from foods. Exercise and changes in lifestyle habits are not addressed.
Get the Skinny on the Atkins Diet
The Hype:
"The amazing no-hunger weight-loss plan that has helped millions lose weight and keep it off."
How It Works:
Atkins' states that consuming a high level of carbohydrates causes overproduction of insulin, leading to increased hunger and weight gain. Instead of focusing on a low-fat, high-carbohydrate plan, he advocates almost the opposite. Carbohydrates are limited to only 15-60 grams per day, while protein and fat are highly encouraged. Atkins' states that such a plan suppresses hunger, increases fat burning, and helps stabilize blood sugar levels which therefore decreases food cravings.
Fact or Fiction?
Fiction, according to most health professionals. Stephen Barrett, MD, a nationally known author and consumer advocate against health fraud, includes Dr. Atkins' books in his list of non-recommended reading and states they are "unreliable because they promote misinformation, espouse unscientific theories, and/or contain unsubstantiated advice." Any diet that limits carbohydrate causes the body to rely on fat or muscle for energy. When our body breaks down stored fat to supply energy, a byproduct called ketones are formed. Ketones suppress appetite, but they also cause fatigue, nausea, and a potentially dangerous fluid loss. Anyone with diabetes, heart, or kidney problems should NOT follow a diet that promotes the formation of ketones.
The Skinny:
Don't waste your money or health on this plan. Dr. Atkins promises more than he can deliver, and his recommendations are the opposite of current health suggestions. Yes, weight loss is possible following his guidelines. But you will likely pay the price in decreased health and yet another failed diet. Instead of temporary relief, why not try the sensible method of moderately decreasing calorie intake while gradually increasing exercise. It works.
Get the Skinny on the Diet Patch
The Hype:
"Non-Drug -- Safe -- Easy to Use -- Never Hungry -- No Side Effects"
"Be slim, be trim, be beautiful!"
The various diet patches I've reviewed promise to:
· control appetite
· stimulate metabolism
· nourish the muscular system
· eliminate toxins
· reduce water retention
· reduce fatigue
And they hold out the hope that you will:
· look younger
· have better job opportunities
· find better relationships
· create a cleaner lifestyle
How It Works:
Basically, it doesn't. With all that hype, you are almost forced to believe that a diet patch will not only magically cause weight loss but also save you thousands of dollars in clothing costs (why bother with the latest fashion if you're suddenly irresistible?) and therapist fees (a diet patch appears to be a simple way to cure every problem in life). Diet patches have never been adequately studied, so they rely solely on individual testimony as to their effectiveness. They try to mimic prescription transdermal patches that are used successfully for motion sickness, yet the diet patches that have been subjected to scientific evaluation contain primarily adhesive and either algae or seaweed. According to their product literature, some magical, "all-natural" potion is absorbed through the skin that miraculously causes you to lose weight.
Fact or Fiction?
According to the Food and Drug Administration, diet patches have not been shown to be safe and effective and have never received FDA approval. In fact, the FDA has seized millions of dollars' worth of a variety of diet patches over the past 10 years. Some diet patches include instructions that state to "keep in mind the need for a healthy, well-balanced diet and suitable exercise program" for optimum success. Why bother with the patch?
As with many other weight-loss products, diet patches are promoting a miracle cure. There is no scientific reason they should work, and in fact they don't.
Our Advice:
Spend the $50 a month it costs for diet patches on a health club membership instead.
Get the Skinny on Metabolife
The Hype:
Metabolife bills itself as an "herbal-based diet and energy supplement, formulated to raise metabolism and create a thermalgenic response to burn fat, not muscle."
How It Works:
According to the label on the bottle, Metabolife contains a long list of herbal supplements, including Guarana and Ma Huang concentrates. Both are well-known stimulants that work like super-charged caffeine. The company promises that Metabolife will raise energy levels and curb appetite while burning body fat. They do recommend eating regular meals and drinking plenty of fluids due to the diuretic effect of some of the ingredients. They also encourage checking with a physician before using this product.
Fact or Fiction?
In 1996 the Food and Drug Administration (FDA) issued a warning about both ephedrine and guarana. Both herbs are potent stimulants, with possible effects on the heart and nervous system. Mild symptoms can include:
· nervousness
· dizziness
· tremor
· headache
· or stomach upset.
More dangerous symptoms include:
· chest pain
· seizure
· heart attack
· and psychosis.
Adverse effects have been reported in both young, healthy people and consumers with existing chronic illness such as high blood pressure. In addition, an overdose syndrome has been identified in children and teens who have used these products, where small amounts have the possibility of causing dangerous side effects.
Anyone with any type of heart disease or high blood pressure or a neurologic condition should not take Metabolife, or any supplement containing ephedrine or guarana. These products also should not be used by pregnant women or any woman considering becoming pregnant.
Anecdotal reports from people who have used Metabolife typically show good results in weight loss, however this loss comes at a high price in terms of our health. The laundry list of herbal ingredients are unsubstantiated for weight control, and some of them pose definite health risks.
My Recommendation:
Avoid Metabolife to protect your life.
Tips for Evaluating Fad Diets
When considering a weight-loss program, look at your lifestyle and personal needs, and be sure you consult your physician before making any drastic changes, especially if you take any medications.
by
Lynn Grieger, R.D., C.D., C.D.E.
iVillage.com