About 60% of adults say they would like to lose 20 pounds, according to a report by NPD, a global research information company that has tracked our diet habits for decades. Boomers are about twice as likely to be dieting as Millennials, according to an NPD report in 2014.1
If you're in that 60%, wanting to lose 20 (or more) pounds, and mulling over which diet to try next, you probably want to know how to maximize the loss on whatever diet you pick. OnTrack Diabetes gathered information from four registered dietitians who spoke on three popular diets at a recent Obesity Medicine Association Summit—Mediterranean, Vegetarian, Low Carb. We backed up their input with recent medical research about how the plans stack up for weight loss.
But first, advice about picking a plan.
Before committing to a diet—or, more appropriately, an eating plan, since it will be for life—think about long-term, says Carrie Dennett, RDN, MPH, a registered dietitian in the Menu for Change Program in Seattle's Polyclinic. "Think about your style of eating," she says.
If you have never been much of a meat eater, low-carb is probably not your best plan, she says. Vegetarian might be a better choice. If you can easily pass up the bread basket at a restaurant, low-carb might work well. Mediterranean can seem the most indulgent, as red wine and olive oil are on the menu, but moderation is the key.
Whatever plan you decide on, limit eating out, Dennett says. "Most meals we prepare at home are going to have fewer calories and be healthier," she says. If you can't avoid eating out, you need to be vigilant and learn to make special requests such as hold the butter, skip the bread basket, substitute more vegetables for bread, fruit instead of French fries, and so on, she says. Or find restaurants with healthier menus.
Now, the scorecard on what each diet is and how it stacks up for weight loss.
Description: Eating Mediterranean means a high intake of vegetables, fruits, beans, lentils, whole grains, olive oil and nuts, with moderate consumption of seafood and red wine (with meals) and a low intake of red or processed meat and dairy products. The focus is on protein-rich foods, heart-healthy fats (olive oil), low-glycemic carbs (such as whole wheat bread, most fruits, non-starchy vegetables such as broccoli and salad greens), vitamins, minerals and fiber. Low-glycemic carbs don't make blood sugar shoot up quickly.
Weight loss: "The research on the Mediterranean diet for weight loss isn't as robust as for heart health and metabolic health," Dennett says. However, there is some evidence that Mediterranean diets that limit refined carbohydrate foods in the evening can produce weight loss, she says.2
In another study, experts found that combining the Mediterranean diet with walking can produce a loss, and worked better for those with diabetes than those without it. The researchers evaluated 339 men and women, average age 56, including 124 with diabetes, who followed a Mediterranean diet and were given an individually prescribed walking program. Among those with diabetes, the average weight change was about 2.6 pounds at six months, 3.3 pounds at a year, and more than 8 pounds at the two-year mark (with 93 people still reporting in). Those without diabetes had lost less than a pound, on average, by two years .3
Beware: Eating Mediterranean is not an excuse to indulge in red wine. Intake should be moderate (the classic definition is one drink daily for women, two for men) and with meals.
Description: A vegetarian diet is plant-based and meatless, with protein sources coming from beans and nuts. A vegan diet, stricter, eliminates dairy and eggs. However, vegetarian eating has room for flexibility, says Anita Bermann, RDN, MS, a dietitian in Bainbridge Island, Washington. If a strict meatless diet is too difficult, she urges people to adopt a flexitarian plan—mainly plant-based but with occasional meat or fish. Think about reducing meat, she says, rather than eliminating it.
Weight loss: Vegetarians, in general, have a lower body mass index (BMI) than do non-vegetarians, according to the Adventist Health study, a long-running look at vegetarians and how they compare with meat eaters. The experts found non-vegetarians had an average BMI of 28.7 (25 is overweight, 30 and up obese).3 The strictest vegetarians, vegans, had an average BMI of 23.6, followed by lacto-ovo vegetarians (who eat eggs and dairy) at 25.7, then pesco-vegetarians (who eat fish) at 26.3 and semi-vegetarians at 27.3.4
In a large review of vegetarian diets, experts looked at results when about 1,100 men and women were assigned to eat vegetarian or non-vegetarian for 18 weeks. Those on the vegetarian plan lost about 4.5 pounds more than the non-vegetarians.5
Beware: Some vegetarians fall into a pasta-and-cheese mode, Dennett says. "Cheese is a great source of protein, but be careful of the amounts," she says. "Focus on flavorful cheeses, like feta," she says. A small amount usually is satisfying.
Description: While there are many definitions of low-carb, three main patterns are popular, according to Megan Moore, RD, CD and Laura Eggerichs, RDN, CD, both clinical nutrition specialists at Swedish Medical Center, Seattle. They are:
Weight Loss: As carbohydrate intake decreases and protein increases on low-carb plans, that can be good news on the scale, Moore and Eggerichs say. Eating 1.5 g of protein per kilogram of body weight can result in weight loss, research has found.6 To translate: A 150-pound person(68 kg) would eat about 102 g of protein daily to lose weight. Three ounces of salmon has 19g of protein, 3 oz of tuna has 23. Those on a low-carb diet can end up needing less insulin or metformin, Eggerichs says, and that, in turn, can help to minimize weight gain, she finds.
Beware: Don't assume you can eat unlimited bacon and pepperoni, Dennett says. Limit processed meats and go for the leaner cuts.
No matter what plan you follow, it's not the diet, it's the behaviors that produce weight control, Dennett says. Here the most common behaviors that trip up dieters, she says.