Baby Food, CarbLovers, HCG Diets and More: Which Fad Diets Work?

What It Is:

The Baby Food Diet was first promoted by celebrity trainer Tracy Anderson, and advises its followers to substitute tiny jars of baby food for higher-calorie snacks and meals. The theory is that bland, mushy baby food served in portion-controlled jars will prevent overeating and keep you satisfied with smaller portions of food at fewer calories. The basic plan calls for eating 14 jars of baby food throughout the day, with an option to have a normal adult meal at dinner. Another option is to have three healthy adult meals per day, and swap higher-calorie snacks for baby food.

Expert Verdict:

Katz: This diet is more of a silly gimmick but not harmful. Baby foods tend to be relatively simple, wholesome foods- and thus, arguably, could make for a convenient, nutritious snack. But there are many wholesome food and snack options for adults that don't require eating mushy foods designed for babies. I suspect most people will quickly tire of eating baby food, and once they "fall off the wagon/stroller" they will gain back any weight lost. This diet, too, is about a specific food choice, not about the whole skill set required for sustainable, healthful eating and weight control. This diet is not directly at odds with health, depending on which baby foods are chosen, but because it is unlikely to be sustained over time, it is also unlikely to promote health over time.

Ikeda: Since jars of baby food range from 15 to 100 calories, people could actually gain weight by following this baby food diet. The basic plan calls for eating 14 jars of baby food throughout the day, with an option to have a healthy adult meal at dinner. Most dietitians recommend mothers make their own baby food by pureeing good tasting fresh food. Frankly, I don't know how anyone could force themselves to eat 14 jars of mushy tasteless processed stuff.

Ayoob: This diet works becuase the portions are controlled and because it doesn't really lend itself to much overeating, unless you really like baby food. Would I recommend it? No. Most dentists would probably agree with me. When it comes to teeth, use them or lose them. We need to chew. Baby food also tends not to have lots of added fats, sugars, and sodium, but there are exceptions. The combination foods can include such things, as can the desserts, so you still have to read labels. The pros of the diet are that you have portion control and you can have simple food if you choose wisely. The cons are, um, it's baby food! Also, everything is pureed or mashed into oblivion, so there's way less fiber, even if you're eating a lot of fruits and vegetables. The diet is very gimmicky and no one is likely to stay on this diet for very long.

What It Is:

The HCG Diet is based on the premise that the HCG (human chorionic gonadotropin) hormone produced during pregnancy works in nonpregnant adults as an appetite suppresant. HCG is a hormone first produced by the developing embryo and then the placenta during pregnancy to help nourish the womb. Because calories are rerouted from mother to fetus during pregnancy, HCG diet promoters say injecting the hormone will help curb appetite and allow dieters to get through a day on the energy equivalent of a turkey sandwich. The diet's creators claim that following the HCG protocol means a weight loss of 1 to 2 pounds per day. A person on the HCG diet is allowed only 500 calories per day of protein, fruits and vegetables, and only light exercise is recommended. A 26-day kit of the hormone costs around $100.

Expert Verdict:

Katz: This diet is utter and dangerous nonsense. A 500 calorie per day diet can be lethal, as was seen with very low calorie liquid diets in the 1970s and '80s. Such severe calorie restriction can leach vital proteins from the heart, causing lethal dysrhythmia. The severe calorie restriction is the only basis for weight loss on this diet, and even when it works, it is not sustainable. This diet is at odds with health.

Ikeda: This diet was very popular in the 1970s, just about the time I was starting my career as a registered dietitian. I guess the promoters figured that if Atkins could resurrect his diet and make many millions, they could do the same. At that time, HCG was isolated from the urine of pregnant women and given as an injection. It appears that it is now possible to synthesize HCG in the laboratory and provide it in liquid form. At least I hope that's the case, and it isn't urine in those little bottles! This diet makes the claim that it will save you money. Of course, the HCG kit costs $100 for a 26-day supply, so you aren't likely to save too much money. It appears that very few HCG promoters have read the research articles published in the 1970's and 1980s. Well, I have read them, and they all say the same thing: It doesn't work!

Ayoob: There is absolutely no scientific basis for this diet. Even the website offers no scientific support (red flag). It's a hormone isolated from the urine of pregnant women and it's been around for years, but it made a big blast about 30 years ago, then it went under the radar again. It faded because it didn't work, and it will probably fade soon because it still doesn't work. It purports to promote weight loss of 1 to 2 pounds per day. Weight loss that rapid cannot be fat loss (another red flag), just water loss. The website says you'll lose weight because you'll be eating less food. That could be true on any diet, and the only way you lose weight on this diet is by eating fewer calories. Period. No surprises here, it's a gimmick, and you'll save even more money by eating a balanced, low-calorie diet and saving the $100 cost of this 30-day "kit."

What It Is:

Developed by the editors of Health magazine, the CarbLovers' Diet puts the anti-carb diet philosophy on its side, contending that carbs do not make you fat but instead shift your body into fat-melting mode and keep you full longer.

The diet cites a University of Colorado study that found the slimmest people eat the most carbs. The diet specifies that users should focus on increasing the amount of "resistant starch" in their diet. Resistant starch is a type of carbohydrate that resists digestion in the small intestine, making you feel full longer while helping to control blood sugar levels and cravings, and boosting metabolism.

Users begin the diet on a 7-Day "CarbLovers Kick-Start" plan, followed by a 21-Day "Carb Immersion Plan." The diet's creators promise to help its followers shed up to 6 pounds in the first week by eating normal healthy foods along with "carb stars" rich in ingredient-resistant starch. A section on exercise reinforces the importance of regular physical activity, along with the diet plan. To increase the amount of resistant starch in your diet, the plan calls for choosing at least one "carb star" food at every meal, such as green bananas, beans, lentils, oatmeal and brown rice. No food groups are eliminated and substitutions can be made to fit the plan to personal preferences.

Expert Verdict:

Katz: While this diet touts resistant starches, it really is a diet that emphasizes beans, whole grains, vegetables and fruits. So, in other words, it really is a healthful, calorie-controlled diet, wrapped in a gimmick to help market it. The diet makes a point of including foods such as potato chips as part of its marketing. By disguising the fact that the diet really is about eating well, it may invite its participants to do otherwise. If they really indulge in all 'carbs' without being devoted to wholesome foods, weight is apt to be regained. The emphasis seems to be exclusively on food choice, rather than the whole skill set required for sustainable, healthful eating and weight control. But, overall, this diet really places an emphasis on a plant-based diet. If this diet guides people to choosing more wholesome, plant foods, and stick with them, there could be health benefits.

Ikeda: On the CarbLovers' Diet website, Grammy Tammy testifies that she started the CarbLovers Diet yesterday and she already feels better and has lost 2 lbs!!! Just think, Grammy could lose 120 pounds in two months. There are lots of other success stories on the website, so if you believe in fairy tales you might want to read them. But if you are a nonbeliever, then don't waste your time!

Ayoob: This diet does pay attention to portions and total calories, which is how all weight loss ultimately occurs, but it also gives people a break by not excluding foods that people like, and are probably going to include eventually anyway. The CarbLover's Diet does give a nod to healthy foods that have fiber and are more likely to keep you feeling full for longer. The diet tells the reader that there's room in a balanced diet for pasta, baked potatoes and bananas, and that they can be healthy. This will be very appealing to readers who are tired of being demonized for liking carbs or thinking that pasta or potatoes are bad. Carbs can be a vehicle for added fat (potatoes with butter, pasta with olive oil, you get the idea) and if you're used to eating large volumes of food, you may want to lean toward the high-fiber, low-cal carbs, at least at first. There's no free lunch here, but the authors don't promise one either -- just a lunch that can fit in some carbs.

Web Extra: Click here to view a sample "CarbLovers' Diet" meal plan.

What It Is:

The Dukan Diet is the diet book written by Dr. Pierre Dukan that has taken Europe by storm, with sales of 3.5 million in 14 different languages. It emerged on the royal wedding scene earlier this year, with Kate Middleton's mother, Carole, reportedly ascribing to the regimen it espouses.

Some experts have compared the approach to the Atkins Diet because a phase of it involves a high-protein regimen. It is a comparison at which those behind Atkins have bristled, noting in a December 2010 press release that "the Dukan Diet is just another variation of the Atkins Diet, but with some nutritional recommendations that simply don't make sense or are guaranteed to fail." It remains to be seen, of course, whether the Dukan Diet will parallel the financial success of the ubiquitous Atkins.

The diet encourages dieters to eat as much as they want of nonfatty, protein rich foods, including oat bran (a key component) washed down with oceans of water. The second stage introduces vegetables, but no fruit; the third brings with it two slices of bread, a serving of cheese and fruit and two servings of carbohydrates a day, with two weekly "celebration" meals with wine and dessert (the diet is French, after all); and the final stage six days a week of "anything goes" and one day of reversion to strict protein-only stage one -- for the rest of your life.

Expert Verdict:

Ayoob: This is kind of an extreme example of overeating and then letting yourself go. People lost about 1.5 pounds per week, which is pretty much what you would expect.

The downside of it is this: It's probably not a regimen that people can or should stay on for so long. If you stay on a balanced diet, you do pretty much the same thing. It doesn't seem to work as crash dieting.

What is okay for people to do is to undereat a few hundred calories for a few days before treating themselves. You can plan ahead -- undereat 200 calories per day for a few days, which really isn't all that hard to do.

The main problem I have with it is that there is no reason you need to be overlooking fruits and vegetables in any phase. That's not what makes people lose weight; dialing back calories does.

What It Is:

The 4 Day Diet is the brainchild of Dr. Ian Smith, author and diet consultant for VH1's "Celebrity Fit Club," who found that people were not complying with their diet plans because they suffered from "food boredom."

"People get tired of eating the same thing over and over again," Smith said. "This is a way to move the food around so people are eating good food and don't get tired of eating it because they know new foods are coming. ... Even if they were in a tough phase, they knew it would only last four days. From a psychological standpoint, that's a great boost."

Smith's plan is based on seven mix-and-match, four-day-long modules that consist of a defined food group or plan. For example, the Induction module is meant to detoxify and cleanse the system, while the Protein Stretch module incorporates foods such as eggs, lean meat and vegetables; the Smooth module allows people to indulge in forbidden favorites such as pizza. Together with exercise, Smith said his modules keep the body from becoming accustomed to one diet plan.

Expert Verdict:

Katz: Obviously, there is no science to back this up. The ultimate goal of "dieting" should be to establish a stable, healthful dietary pattern. I see no hope whatsoever of that here. So this is all about, and only about, short-term weight loss -- which just about any diet can provide. What is the right answer? Learn to choose wholesome foods; learn to use them in wholesome meals; and make a lifelong commitment to healthful eating and regular activity that includes the other members of your household. That's the truth.

Ikeda: Like most diets, this one can result in weight loss. My big criticism of this diet is it does not teach people how to eat a healthy, well balanced, nutrient-dense diet that they can keep eating for the rest of their life. And I don't care how well one eats, if a person is not physically active, they are not going to be healthy.

Ayoob: This diet has some nice aspects to it, but balance isn't one of them. There are lots of different calorie intakes over the four days; some are really low, some not. It's different each day, it's not boring. It encourages you to keep a food diary. It allows you an occasional indulgence so you don't feel deprived. Lots of fiber, fruits and veggies. I especially like that it includes beans -- a terrific food. But some dieters will find that they need at least some consistency.

What It Is:

The Flat Belly Diet, launched by Prevention magazine editor-in-chief Liz Vaccariello, is built around a 1,600-calorie-per-day strategy that allows dieters to eat four meals per day selected from hundreds of meal possibilities.

Central to the diet is the principle that every meal must contain a source of MUFA, short for monounsaturated fatty acids. According to the diet's proponents, these predominantly nut-based oils can target-reduce dangerous belly fat. The diet also commences with a four-day jump-start to get rid of abdominal bloating, during which a dieter drinks what the proponents of the diet call Sassy Water, a lemon- and ginger-containing beverage named after Prevention nutrition director Cynthia Sass.

The diet's creators cite a small, Yale University Prevention Research Center MRI study that found the diet reduced visceral belly fat on average by 33 percent in 28 days for nine overweight women in its success. Other risk factors, such as high cholesterol and blood pressure, were also reduced in study participants.

Expert Verdict:

Katz: The diet is generally healthful, with an emphasis on foods noted as being good for insulin resistance. My lab actually studied the effects of this short term, and they were quite good.

Ikeda: This diet is based on the premise that a higher intake of monounsaturated fatty acids will result in a flat abdomen. There is nothing in the scientific literature that substantiates this claim. The best way to get a flat belly is to increase the strength of abdominal muscles by exercising them.

Ayoob: You may have a flatter belly in 32 days, but that's because you're losing weight, pure and simple. Make no mistake, your body will determine where you lose weight. It tends to come from the belly first anyway -- that's usually the body's first preference -- but it's the weight loss that's flattening your belly, not some diet miracle.

What It Is:

The so-called "full-fat diet" builds off January 2007 Swedish research that found that women who had at least one serving of milk (whole milk, to be exact) or cheese each day experienced less weight gain over the following nine years than their counterparts who did not. Some concluded from this research that other full-fat daily foods may also provide these weight loss benefits, though the researchers behind the Swedish study hesitated to delve so deeply into the results to make a similar claim.

While the full-fat diet has many different versions, one of the most prominent proponents of eating foods in their full-fat form is New York-based nutritionist Esther Bloom, who delivers such advice in her book, "Eat, Drink and Be Gorgeous."

Expert Verdict:

Katz: I didn't find enough information about this to make a judgment, but the usual promises were made.

Ikeda: Although Esther Blum is a registered dietitian, which gives her a plus for credibility in my book, her enthusiasm for supplements negates that plus with a minus. None of the endorsements on her website come from credible nutrition experts.

Ayoob: I like the non-diet mentality of this diet. It's the idea that you can have your cake, and eat it too. But the diet is clear that you can't have it all the time and in all amounts. It's the idea that nothing is forbidden, and that's good.

What It Is:

In its purest form, the Mediterranean diet is designed to emulate the food choices of those who live in areas on the Mediterranean Sea, such as in Italy and Southern France. A true Mediterranean diet is predominantly plant-based, with plenty of fruits and vegetables, grains, beans, nuts, seeds and olive oil. It also incorporates some cheese, yogurt, fresh fish and poultry, with very little red meat.

Most nutrition experts caution that the Italian fare served at many Italian restaurants in the U.S. -- which is heavy in cheese, meat and fat -- should not be confused with a Mediterranean diet.

Expert Verdict:

Ikeda: In looking at the [figures] below, one has to conclude that eating the way the French and Italians do might be quite beneficial.

Percentage of people classified as obese:

USA: Female = 34 percent; Male = 27.7 percent

Italy: Female = 9.9 percent; Male = 9.5 percent

France: Female = 7.0 percent; Male = 8.0 percent

Source: The UK Food Standards Agency

Ayoob: This diet is famous for olive oil. Olive oil is great and it's heart-healthy, but it has as many calories as any other oil, even the less healthy ones. As such, the more olive oil you eat, the smaller your other portions are going to be. It's true that fat helps you feel satisfied, and this diet also focuses on lots of fruits and veggies, but it can be a little low in calcium, as dairy is not a huge part of the Mediterranean diet. I would modify it to include low-fat milk.

What It Is:

While there is no single "Detox" diet, all are built around the idea that, by eating, or avoiding, certain foods, you can cleanse -- or "detoxify" -- your body. The toxins that are purportedly eliminated from the body through these diets are most often identified as chemical pollutants from the environment, along with supposedly harmful byproducts of human metabolism that linger in the body's tissues. Most Detox diets are intended to be temporary, lasting a few days or a couple of weeks.

Detox diets also provide a constant source of fodder for celebrity magazines, as stars including Gwyneth Paltrow, Angelina Jolie and Beyonce Knowles have reportedly tried them in the past.

Expert Verdict:

Katz: All Detox diets are rather silly. The body detoxes itself just fine. No real 'there' there.

Ikeda: Doesn't anyone remember the lessons in human anatomy and how the body functions that were taught in elementary, middle school, and high school? Well, if one did remember, then one would realize that the body is self-cleansing -- like a self-cleansing oven. We get rid of 'toxins' daily in urine, feces and sweat. If we didn't, we would be dead in a matter of days.

Ayoob: This one is temporary; it's meant to be temporary, and that's not going to be of much help to most people. Even temporarily -- several days to a week -- it's a bad idea. It's mostly about fruits, steamed veggies and not much protein at all. Bad idea. Stick to this diet strictly and you'll be losing muscle mass -- and that's your calorie engine. Detox diets may have been around for years, but so has fasting, and I wouldn't recommend that as a means of weight loss either. Period.

What It Is:

The Zone Diet, developed by Dr. Barry Sears, purports to balance the body's hormone levels within a specific range by controlling the foods that are consumed. The diet's website describes the plan as a, "moderate-carbohydrate, moderate-protein, moderate fat diet that has approximately one gram of fat for every two grams of protein and three grams of carbohydrates."

The Zone Diet places special emphasis on the moderate intake of low-fat protein, low glycemic-load carbs (such as those found in fruits and vegetables), and monounsaturated fats, as well as all needed nutrients.

Expert Verdict:

Katz: I think this is too high in protein. It works by providing a strict dietary discipline, but suffers the same problem with sustainability as the others.

Ikeda: Another oldie that had no impact whatsoever on the obesity epidemic in this country.

Ayoob: This one is fairly moderate, focusing on a good amount of lean protein, moderate fat and moderate carbs. Skip the vegetarian version if it's not your thing.

What It Is:

Despite the names of these popular diets, both the Cleveland Clinic and the Mayo Clinic deny having any association whatsoever with them. This, however, does not seem to have impacted the popularity of either of these regimens, both of which are subjects of a high volume of Internet searches by those hoping to lose weight.

The so-called "Cleveland Clinic 3-Day Diet" features a strict menu that is heavy on black coffee and light on calories. Proponents say those who follow the diet can lose up to 10 pounds in three days. The so-called "Mayo Clinic Diet," on the other hand, features a great deal of grapefruit juice and few, if any, carbs.

Editor's note: The grapefruit-based "Mayo Clinic Diet" should not be confused with Mayo Clinic's own version of the "Mayo Clinic Diet," which emphasizes healthy eating and lifestyle-related changes. The expert comments below do not apply to the official regimen supported by the Mayo Clinic.

Expert Verdict:

Katz: These look ridiculous; they simply provide a detailed meal plan that restricts calories. As soon as you stop following these detailed directions, it's all over.

Ikeda: If these diets worked, the Cleveland Clinic and Mayo Clinic would proudly take credit for them. They would publish books about them and make money off the sales. The problem is, these institutions are too ethical and know the diets don't work, so they distance themselves for good reason.

Ayoob: First, skip any 3-day diet. If it's not meant for more than three days, you're likely just maximizing water loss, not much else. Go off the diet, the water weight returns and you've lost three days that could have been spent working on sensible eating. Any diet that only lasts a few days or a few weeks is a diet to be avoided. Better to get on some sneakers and do a fast walk away.

What It Is:

The Atkins Diet was first popularized in 1972, with the release of the book "Dr. Atkins' New Diet Revolution." Controversial from the start, the diet is built around the idea that consuming too many carbohydrates is the main factor behind overweight and obesity. Therefore, by drastically reducing the intake of carbohydrates and shifting over to a diet high in protein in fat, a person can force his or her body to burn stored fat more efficiently.

The Atkins diet gained momentum at the beginning of the decade, and diet authors have published a host of new books aimed at further delving into the benefits of a low-carb approach to weight loss.

Central to the diet is the principle that every meal must contain a source of MUFA, short for monounsaturated fatty acids. According to the diet's proponents, these predominantly nut-based oils can target-reduce dangerous belly fat. The diet also commences with a four-day jump-start to get rid of abdominal bloating, during which a dieter drinks what the proponents of the diet call Sassy Water, a lemon- and ginger-containing beverage named after Prevention nutrition director Cynthia Sass.

The diet's creators cite a small, Yale University Prevention Research Center MRI study that found the diet reduced visceral belly fat on average by 33 percent in 28 days for nine overweight women in its success. Other risk factors, such as high cholesterol and blood pressure, were also reduced in study participants.

Expert Verdict:

Katz: I think this is a silly diet at odds with health. It restricts choice very severely, which, in turn, restricts calories severely, so it, of course, produces short-term weight loss. But cutting out 'carbs' long term makes no sense; everything from lollipops to lentils is a 'carb,' so this diet throws out the baby with the bathwater.

Ikeda: Is this old thing still around? If it worked, obesity would no longer be a problem in this country, since a good percentage of the population has tried it.

Ayoob: This is the original 'Full-Fat Diet.' Isn't America over this one yet? For people who plan to ditch their resolutions, this diet is for them -- people don't tend to stay with it very long. Just understand that when you finally let go of this diet, you'll have to go for something more realistic and not so limiting. Why not do that right from the start?

What It Is:

While no single, definitive grapefruit diet exists, all are based around a low-calorie approach, combined with a lot of grapefruit and grapefruit juice. The inclusion of this fruit is based on the idea that grapefruit contains a certain chemical or enzyme that aids weight loss.

Most of these approaches are short-term weight loss diets, lasting anywhere from a few days to a little more than a week.

Expert Verdict:

Katz: Diets based on a single food work by restricting choice. But, over time, restricting choice is incompatible with both health and dietary pleasure. Unsustainable.

Ikeda: I wonder how many vitamin deficiency diseases one could achieve by staying on this diet long enough? Quite a few, but, rest assured, it wouldn't be scurvy [a disease resulting from a deficiency of Vitamin C] since we all know that grapefruit gives us the big [Vitamin] C.

Ayoob: Back to the "Mayo" diet, there are grapefruit versions of this, and the "Mayo" diet was also akin to the 'Cabbage Soup' craze in the '80s. Skip them. They're 10- to 14-day temporary fixes.

What It Is:

The South Beach Diet, developed by cardiologist Dr. Arthur Agatston, is a three-phase plan intended to help adherents lose weight in the short term and keep it off long term. Of the three phases, the first is the most restrictive, especially when it comes to carbs. Dieters are instead encouraged to include lean protein and high-fiber vegetables in their meals. Phases 2 and 3 gradually reintroduce non-refined carbohydrates and other dietary elements.

The diet plan also encourages exercise as a part of the diet, a feature that proponents say distinguishes it as a healthy lifestyle rather than simply a diet.

Expert Verdict:

Katz: Surprisingly silly and short on substance, given the size of the following: Cut out a lot of foods, add some back, then add some more back. At that point, if you start regaining weight, cut them all out again.

Ikeda: Where are the sequels? I'm waiting for the 'North Beach Diet,' the 'West Beach Diet' and the 'East Beach Diet.' Or perhaps we need an 'Any Old Beach Diet.'

Ayoob: This one is pretty moderate. Developed by a cardiologist, it's heart-healthy. It tends to penalize refined carbs. They're really OK; just watch portions and go for whole grains whenever you have the choice. It also focuses on exercise, and that's the other part of the diet puzzle. Activity -- you've got to have it, or the diet works a heck of a lot more slowly.