4 Fad Diets: The Good, the Bad and the Ugly

A registered dietitian dissects popular weight loss trends

Diets promising rapid and dramatic weight loss are always plentiful and popular. Some fads do help to people drop pounds, but more often than not, the results aren’t sustainable and the methods used to lose weight aren’t safe. Denise Reyes, a registered dietitian at Scripps Health in San Diego, takes a look at a four popular diet fads, breaking down the pros and cons of each.

Baby food diet

The baby food diet encourages the consumption of baby food to lose weight. Dieters are supposed to eat a combination of pureed vegetables, meat and fruit for breakfast and lunch, and one well-rounded adult meal for dinner.

Pros: Since baby foods are often advertised as being organic, additive-free and full of vitamins, this makes them seem like an easy, convenient way to eat healthily, limit calories (jars are 15 to 100 calories each) and control portion size.

Cons: Since baby food is made for babies, it does not meet adults’ nutritional needs. Plus, if a dieter eats 14 jars of baby food a day, that person could consume up to 1400 calories and still be hungry. “Part of what lets our brains know we are feeling satiated is the act of chewing. Baby food doesn’t require any chewing,” says Reyes. “The baby food diet does not really allow for much variety and would become difficult to sustain after a few days.”

Blood type diet

The blood type diet recommends people eat or avoid various foods depending on their blood type. For instance, the diet recommends that those with Type A should eat a vegetarian diet and steer clear of meat to avoid bloating. Type O’s should eat meat and seafood, but avoid grains, legumes and corn to prevent weight gain.

Pros: In the Type A case, if you go from being a heavy meat eater to eating more vegetables, you might lose some weight and eat less, says Reyes. “None of the foods on this plan are bad for you,” she explains. “I’m not a big fan of eliminating food groups such as grains unless you have a known intolerance or allergy.”

Cons: The blood type diet is unsupported by scientific evidence. Plus, it may require radical changes in the types of foods you eat. “If you’ve been a meat-eater all of your life, it could be difficult to switch to a vegetarian lifestyle,” says Reyes. “If you can’t sustain the diet—even if it’s a great plan—it’s not going to work in the long run.”

Grapefruit diet

The diet is based on the claim that grapefruit has properties that speed fat-burning. The diet calls for the consumption of half a grapefruit at every meal.

Pros: The grapefruit diet restricts high-carb and starchy foods like beans, corn and potatoes. Since these foods contribute to water gain, Reyes says dieters may notice some weight loss thanks to retaining less water. Plus, grapefruit is a good source of fiber, so it may help fill you up before eating a meal.

Cons: This diet is very restrictive. While it promotes eating meat and other high-protein foods, the only carbs allowed—besides grapefruit—are greens and milk. Some versions of this diet also call for no snacking between meals.

“Anytime you start a diet, especially one that restricts carbs, you’ll see a lot of water weight loss,” says Reyes. “But once you reintroduce carbs, the weight comes right back.”

Paleolithic (Paleo) diet

Also known as the caveman diet, the paleo diet encourages eating foods that were available during the Paleolithic era—which ended thousands of years ago. Today, that diet would include lean, grass-fed meats, wild-caught seafood, organic fruits and vegetables, eggs, roots and nuts. To quench their thirst, paleo dieters drink water, coconut water or green tea.

Pros: This diet promotes eating organic, wholesome, homemade and even raw foods that are protein-rich and filled with fiber, which could lead to weight loss.

Cons: This diet restricts dairy, grains and legumes—even referring to these foods as ‘cheats.’ “It cuts out food groups that we know are good for us,” explains Reyes. “When foods are referred to as ‘cheats,’ it implies there should be a sense of guilt when you eat them. Feelings of guilt do not usually fit well into a healthy, sustainable eating plan.”

The paleo diet is a proponent of using coconut oil and coconut milk. “Coconut products may have been fine for cavemen who expended a lot of energy, but they are high in saturated fat which may not fit well with a more sedentary lifestyle,” she says.

Overall, Reyes says most of these diets—except the one that encourages the consumption of baby food—may make you more aware of what you’re eating. But quick fixes don’t produce lasting results. “When trying to change your eating behavior, think of your effort as a journey that requires small, realistic changes that make sense in your life,” suggests Reyes. " It is an opportunity to be adventurous and creative with a new outlook on eating that incorporates healthy, wholesome food but still retains the feelings of comfort and tradition."

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