Choosing a Diet Program

The basics of a diet focus on healthy, balanced eating. A safe and effective weigh-loss program should include a sensible eating plan that cuts down on calories without eliminating entire nutritious foods or food groups. It should encourage regular physical activity and provide guidance on behavioral and emotional issues that impact your weight. Once you've lost weight, the program should provide a plan for keeping the weight off. Some questions to ask include the following:

Is it low in calories?

This is key to losing weight and is even more important than the proportion of carbohydrate, protein, and fat in the diet. A low-calorie diet also makes weight loss more efficient, as long as it isn't so low that it causes your body to conserve energy.

Does it teach new eating behaviors that can be continued after you lose the weight?

Without this change in perspective, the weight may be regained if you resume your old eating habits.

Does it differentiate between different types of fat?

A diet should emphasize the health benefits of monounsaturated fat and polyunsaturated fat over saturated fat and trans fat. If the diet is not low in saturated fat, trans fat, and cholesterol, your efforts to lose weight may not pay off in lower blood cholesterol.

Is it nutritionally sound?

A diet has to be balanced, with enough foods from each of the major food groups, or it may not provide adequate vitamins and minerals. The diet should include nutritious foods such as fruits, vegetables, whole-grain breads and cereals, nonfat or low-fat dairy products, and lean meats, fish, poultry, or legumes.

Is it safe?

Be sure to ask what are the potential risks of following the weight-loss program. If diet drugs or supplements are part of the program, ask about the possible side effects. If you have a medical condition or are taking medications, talk to your doctor about the program and your weight-loss progress, and ask your doctor to make any adjustments in medications, as needed. It simply does not make good sense to exchange the health problems caused by being overweight for a whole new set of problems brought about by an ill-conceived, potentially nutrient-deficient weight-loss diet.

You should also ask whether a certain diet would fit your lifestyle. The next page offers some questions to help determine if a certain diet is a good fit.

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No single diet is effective for everyone, so you must choose a diet that will work for you. Different weight-loss programs offer a variety of features designed to help you succeed. Choose a plan that fits your personality and the way you live your life.

Does the program fit your dieting style?

Do you prefer to go it alone, following the advice of a weight-loss book or Web site? Do you prefer to receive one-on-one counseling with a registered dietitian? Or do you prefer to share in group support, either in person or on-line? Choose the format that makes you most comfortable, and you're more likely to succeed.

Does the diet fit your lifestyle?

Do the meal plans require you to spend hours preparing fresh meals in the kitchen but you don't have the time or the inclination to cook? If you eat out or travel often, is it possible to stick with the program?

Does the program allow you to eat the same foods as your family?

If the program restricts your food choices so you have to make one meal for yourself and another for your family, you may find it difficult to stay with the program. A plan that controls portions but allows a wide variety of foods may work best for you and your family in the long run.

Is the weight-loss program flexible enough to accommodate the foods you like or does it feature many foods you dislike?

If the plan eliminates your favorite foods or requires you to eat foods you dislike, how likely are you to stick with it in the long run? You're more likely to stick with a program that offers a variety of nutritious foods from all the food groups and that allows you to enjoy moderate portions of some of your favorite foods on occasion.

Can the diet be modified to fit your medical needs?

To lower LDL cholesterol and your risk of coronary heart disease, the weight-loss program should be able to incorporate the diet and lifestyle recommendations of the National Cholesterol Education Program and the American Heart Association. Not all weight-loss programs are low in saturated fat, and some restrict foods that are recommended on a cholesterol-lowering diet. So check out the diet rules and restrictions to help you decide if the program is right for you.

Does the weight-loss program end when you reach your desired weight, or does it continue to help you keep the weight off?

Especially if you relied on pre-packaged, pre-portioned meals, you need to learn how to control your weight while eating store-bought foods that are prepared at home. A good weight-loss program teaches you to adjust your eating plan for weight maintenance, encourages you to engage in regular physical activity, and provides on-going support to help prevent you from re-gaining the weight.

Some people fall into the trap of believing a slick marketing campaign that tells them a diet is right for them. The next page shows you how to separate legitimate diets from fad diets.

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There are many diet plans on the market, so it can be difficult to determine diets that work. To be on the safe side, don't hesitate to ask questions about the weight-loss program to make sure it's legitimate. Just because a diet is trendy doesn't mean it's a good one. Watch out for some common red flags.

The next page will introduce you to the different diet types, making it easier to spot the legitimate ones.

In reality, there are just a few different types of diets. But hundreds of different diets have been promoted for weight loss, and with so many options available, finding one that will help you lose weight but that's also good for your heart can seem daunting. Because marketers use different names to promote them, it can be confusing.

The main features of the most common types of weight-loss diets are described over the next few pages; once you become familiar with them, you will be able to recognize the latest diet trends for what they really are. Before you choose a diet, examine the diet carefully, and discuss it with your doctor or a registered dietitian.

The discussion starts out with fad diets, explained on the next page.

Fad diets will come and go because the field of nutrition is vulnerable to oversimplification and misplaced emphasis. Competent nutritional research expands our knowledge base daily, yet examples of famous people who have lost weight with diets that seem too good to be true continue to get the headlines.

Some good advice is to look at these dietary programs with the same critical eye that you might use if you were buying a new home. Would you jump right in without carefully checking it out? Do you know where to look or whom to contact for reliable information about your potential purchase? Are you buying for the short term or the long term?

Whereas the motto for home buying is said to be "location, location, and location," the motto for choosing your next -- and with luck, your last -- diet should be "nutritional balance, variety, and moderation." For the best results, this approach should be combined with regular physical activity.

You can lose weight and follow that motto on a low-calorie diet. Find out how on the next page.

A low-calorie diet is a low-energy diet. The goal of a low-calorie diet is to create an energy deficit by providing fewer calories than your body needs so that the body has to draw upon the energy stored in body fat.

One pound of body fat stores about 3,500 calories, so to lose one pound, you need to consume 3,500 fewer calories. Experts recommend that you eat 500 to 1,000 fewer calories each day depending on your current weight and how many pounds you want to lose. At this pace, you can lose one to two pounds of body fat per week (500 fewer calories per day x 7 days per week = 3,500 calories = 1 pound per week). Exercise, which burns calories, also helps achieve weight loss.

A low-calorie diet can be recognized by the types of foods recommended and the way they are prepared. Fresh fruits and vegetables; whole-grain cereals and breads; nonfat milk, yogurt, and other dairy products; and lean meats, poultry, fish, and beans make up the bulk of the menu. Fried foods, salty snacks, rich sauces, and sugary, fatty desserts are limited.

Foods are prepared using low-calorie cooking methods. For example, meats, poultry, and fish are roasted, baked, or broiled -- not fried. Vegetables are steamed, boiled, or microwaved without using butter. Oils are used sparingly, and margarine, when used, is the reduced-fat, trans-fat-free type. Very importantly, portion control is stressed.

Although the number of calories consumed has to be reduced before you can expect to lose weight, it is possible to lower your calories too much. A real irony of dieting is that you actually lose more weight if you eat some food rather than if you eat nothing at all. The reason is that when too few calories are eaten, the body protects itself from the energy shortage by using available energy more economically. The body does this by slowing its metabolic rate (the rate at which it uses energy). This shift in the rate of metabolism when food is scarce has its roots early in human development.

As hunter-gatherers, our ancestors could not always count on regular meals. They ate whenever they found food. As protection against the possible ill effects of an unreliable food supply, this metabolic adjustment conserved energy when food was not available.

As the body becomes more efficient at using the energy on hand, it actually needs less. A smaller energy deficit results, and less body fat is lost. To avoid this response, the number of calories you consume generally should not go below your resting metabolic rate (that is, the rate at which your body burns calories when at rest). Resting metabolic rate is about 1,000 to 1,200 calories a day for women and about 1,500 to 1,800 calories for men. Diets that recommend consuming fewer calories than that are best followed only under the supervision of your doctor.

Very-low-calorie diets can do more than simply frustrate efforts to lose weight. If followed for an extended period of time, such diets can also lead to nutritional deficiencies. Eventually, the body will begin to break down muscle protein to provide energy. This loss of muscle also slows the metabolic rate, making weight loss even more difficult. And while a vitamin-mineral supplement added to a very-low-calorie diet may protect against nutritional deficiencies, supplements cannot ward off the loss of muscle protein.

Low-calorie diets are usually low in fat, because fat is high in calories. The next page explains how to eat a healthy low-fat diet.

A low-fat diet is a straightforward way to achieve a low-calorie diet, often used for weight loss, and it has the added benefit of controlling cholesterol.

Fat has more than twice the energy potential (calorie content) of either protein or carbohydrate and slightly more than alcohol. So, as a general rule, foods high in fat will also be high in calories. Most low-calorie diets take advantage of this fact and make a priority of lowering the intake of fat. This conveniently allows a low-calorie diet to also be low in fat, making it appropriate both for losing weight and lowering blood cholesterol.

A low-fat diet is made up primarily of foods that contain carbohydrates and fiber, including whole-grain breads and cereals, fruits, vegetables, and dried beans and peas. A low-fat diet should contain fewer foods from animal sources, which decreases saturated fat, or should replace them with foods that are low in fat or nonfat, such as nonfat or low-fat milk and yogurt.

In addition, a low-fat diet should contain more foods from plant sources, which provide fiber, are low in saturated fat, and do not contain cholesterol. Lean meats, poultry, fish, and low-fat or nonfat milk and yogurt supply protein.

Evidence suggests that low-fat diets result in weight loss primarily because the diets reduce total calories. However, studies show that people on low-fat diets not only lose weight but also benefit by lowering their total cholesterol, LDL cholesterol, and triglycerides. Moreover, in addition to the diet, exercise was shown to reduce cholesterol levels even more, as well as preventing a decrease in HDL cholesterol, which is often associated with low-fat diets. Evidence also suggests that a low-fat diet may offer some protection against certain types of cancer, such as breast and colon cancer.

A low-fat diet is generally defined as containing about 20 to 30 percent of calories from fat, but the Therapeutic Lifestyle Changes (TLC) program, which is recommended by the National Cholesterol Education Program and the American Heart Association for treating high blood cholesterol, allows 25 to 35 percent of calories from fat. This higher percentage of fat is permitted if most of the fat is of the heart-healthy variety -- polyunsaturated and monounsaturated -- and saturated fat and trans fat are kept low.

Moreover, increasing unsaturated fats in place of carbohydrates can help reduce triglycerides and raise HDL cholesterol in people with metabolic syndrome. In fact, research shows that in comparison to other types of diets, low-fat diets -- although effective at reducing body fat -- are not necessarily more effective than other weight-loss diets. In other words, a low-fat diet may not be the perfect fit for everyone; other diets that also reduce calories can result in weight loss as well.

If you choose to lose weight on a low-fat diet, cut back on -- but don't entirely cut out -- fat. Dietary fat is essential for the absorption of fat-soluble vitamins, such as A, D, E and K, and polyunsaturated fat provides essential nutrients, such as linoleic acid, which is needed for the production of a group of hormones called prostaglandins that regulate functions of the heart, blood vessels, kidneys, lungs, nerves, and reproductive organs, as well as for growth and healthy skin.

And, of course, fat adds flavor to foods. So add some fat, particularly monounsaturated and polyunsaturated fats, to your daily diet.

A more controversial type of diet is the low-carbohydrate diet, typified by the Atkins diet. Find out how this diet works on the next page.

Many popular versions of this type of diet have evolved over the years, but the Atkins diet is probably the most well known. Low-carbohydrate diets can provide as little as 5 to 10 percent of calories from carbohydrates, although some can provide up to 40 percent of calories from carbohydrates. (The Dietary Guidelines for Americans 2005 recommends 45 to 65 percent total calories from carbohydrates.)

Low-carbohydrate diets are typically high in protein and fat. Breads, cereals, grains, starchy vegetables (like potatoes), and most fruits -- all of which contain carbohydrates -- are restricted, so there are fewer foods from which to choose on this diet. When cutting back on these carbohydrates, the proportions of protein and fat in the diet tend to change as a result.

Ultimately, a person on a low-carbohydrate diet must take care to reduce overall calories; otherwise, it won't result in weight loss. It is possible that a high-protein diet may lower calories overall because protein, in particular, decreases the feeling of hunger, which means you're likely to eat less.

Carbohydrates are the primary fuel for the brain, nerves, and lungs. On low-carbohydrate diets, the body compensates for the lack of fuel by producing acids called ketones that are made from body fat. Besides being used for energy, ketones are also excreted in the urine. Proponents of low-carbohydrate diets claim that using ketones for energy and excreting them in urine burns calories and, thus, facilitates weight loss. In reality, ketones are only used and excreted in small quantities, at the rate of 100 or fewer calories per day.

Initially, large weight losses can occur rapidly on a low-carbohydrate diet; within the first couple weeks, an individual may lose up to 10 pounds. This kind of weight loss can make the diet appealing; however, only a small part of the weight lost during this time is body fat. Muscle protein, which is more dense and heavier than fat, is broken down as fuel for the brain, nerves, and lungs.

The carbohydrate deficiency causes large amounts of salt and water to be lost from the body. In addition, high levels of ketones in the blood can act as an appetite suppressant. Together, these result in a temporary weight loss. When normal eating patterns are resumed, the water and muscle will be regained.

In a comparison of low-fat and low-carbohydrate diets, weight loss at three and six months was about twice as much in the low-carbohydrate group as in the low-fat group. However, at the end of one year there was no difference in weight loss between the two groups, suggesting that long-term adherence to a low-carbohydrate diet may be difficult.

Research indicates that low-carbohydrate diets result in a greater improvement in triglycerides and HDL cholesterol. However, low-fat diets are typically better for lowering LDL cholesterol.

Because low-carbohydrate diets are generally high in protein from animal sources, which are also high in saturated fat and cholesterol, and because they restrict carbohydrates, which limit the only sources of dietary fiber that play a role in lowering blood cholesterol, low-carbohydrate diets are not designed to lower LDL cholesterol. Further research is necessary to determine the long-term effects of a low-carbohydrate diet on heart disease.

A low-carbohydrate diet, and the high levels of ketones it can produce, is not safe for everyone. Many of the vitamins and minerals that carbohydrates provide are essential for pregnant women and their developing babies. For some, especially diabetics, a low-carbohydrate diet can cause blood-sugar levels to fall very low, known as hypoglycemia, which can induce dizziness, fatigue, weakness, irritability, and fainting spells. Cutting down on carbohydrates should be done under your doctor's guidance, especially if you are on any medications, to avoid the potentially dangerous consequences of low blood sugar.

The low glycemic index diet separates carbs into “good” and “bad” forms. The next page explains the low glycemic index diet, including the as-yet inconclusive research on it.

The low glycemic index diet has been used for weight loss, although its value -- for overall health and for weight loss specifically -- is still open to debate.

Originally developed to help people with diabetes better control blood sugar, the glycemic index has also been used to guide weight-loss efforts. The glycemic index ranks foods, particularly carbohydrates, by how quickly they raise blood sugar levels.

Diets based on the glycemic index typically promote eating "good" carbohydrates -- generally whole grains, fruits, nonstarchy vegetables, and beans -- rather than "bad" (refined) carbohydrates because the body digests them more slowly.

As a result, they do not affect blood sugar levels as much. This, in turn, may help you feel full longer, aiding in weight loss. However, the way the body responds to a particular food is affected by a number of factors, including how the food is processed and prepared and the other types of foods eaten along with it. The glycemic index is not a perfect system, and its value in weight loss is uncertain because of limited and conflicting research.

Some studies have linked a higher glycemic index to risk of coronary heart disease or type 2 diabetes. In addition, glycemic load, which takes into account not only the glycemic index but also the actual amount of carbohydrate per serving, has also been linked to risk of coronary heart disease.

In the Nurses' Health Study, women who consumed a diet with a high glycemic load had twice the risk of heart disease as those who consumed a diet with a low glycemic load; this was especially evident in women who were overweight or obese. However, further research is needed to determine whether these types of diets have an effect on the risk of heart disease.

Fasting is an extreme attempt at weight loss and is quite dangerous. Find out more about fasting, including why it's actually counter-productive, on the next page.

Fasting is defined as a temporary abstinence from food and implies a severe restriction of calories. Completely abstaining from food is impossible over the long term, of course, so most fasts are really very-low-calorie diets.

Although calorie intake is greatly reduced in these diets, the loss of body fat is slowed because the body decreases its metabolic rate. This reduction in body-fat loss is camouflaged by the accelerated loss of salt and water. The breakdown of muscle protein brought about by a carbohydrate deficiency is another factor that plays a role in the failure to lose more body fat.

Like the other diets that base their weight losses on limiting carbohydrates, fasting produces quick and impressive results. But these weight losses are accompanied by the possibility of developing hypoglycemia and, if ketone production continues for an extended time, developing ketoacidosis, a serious condition that can lead to coma or even death, if left unchecked.

Weight loss from fasting is only temporary. After all, the body works to maintain balance. Water and muscle protein are replaced once the fasting stops. Consequently, the amount of body fat lost will not be much different from what would be lost on a conventional low-calorie diet, but the price paid in discomfort will certainly be much greater.

There are many diets out there, but only some of them are safe. You have to determine the one that's right for you. With the information in this article, you’ll be able to pick a diet that lets you lose weight and keep it off.

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ABOUT THE AUTHOR

Adrienne Forman, M.S., R.D., is a consultant and freelance writer, specializing in nutrition and health communications. She is the editor of Shape Up America! newsletter, an online publication, and has been a contributing editor of Environmental Nutrition newsletter for the past 14 years. Adrienne is a former Senior Nutritionist at Weight Watchers International, where she was instrumental in creating multiple weight-loss programs, including their popular Points® program.