What to Steal From Keto, Paleo and Other Trendy Diets

What to steal: Fat is not the enemy. The low-fat diet craze that started in the ‘80s may have scared dieters away from all fats. But not all fats are bad fats. “Eating moderate portions of healthy fats can help you lose weight. Unsaturated fats like olives, nuts, seeds and olive oil can help reduce appetite and promote a feeling of fullness,” says Cassetty, adding that these foods also add flavor or texture that improves the appeal of the nutritious foods like veggies they're often paired with.

Paleo

Also known as the Stone Age diet, this approach asks you to eat like a supposed long-ago hunter-gatherer ancestor: If it wasn't served up around the cave fire after a long day of fishing, hunting or foraging, it's off limits. You eat fish, meat, fruits, vegetables, nuts and seeds, and avoid processed foods, grains, dairy and legumes, and added sugar and salt. Proponents say that our bodies evolved to eat only foods available to early humans and that sticking to those can help fend off such modern-day scourges as heart disease, diabetes and cancer while helping you lose weight.

Does it work? Small short-term studies have shown that paleo can help you drop pounds and reduce your waist circumference. Like keto, the long-term weight loss benefits require more research, Smith says.

The downside: This diet excludes beans, chickpeas and other legumes because they are cultivated rather than foraged. “But this category is full of nutrients like magnesium and folate, and are some of the healthiest foods on the planet,” Cassetty says. Plus, in the modern world, it may be difficult to stick with the diet's restrictions.

What to steal: Eat real foods. The standard American diet today is filled with ultra-processed foods and processed ingredients our forebears wouldn't recognize. Limiting these categories as paleo does is a smart idea. Filling up on those caveperson faves — high-fiber, low-cal fruits and vegetables — can help keep pounds off.

16/8 intermittent fasting

With the 16/8 diet, you eat all your daily calories during an eight-hour window, then abstain completely the other 16. You might finish dinner by 8 p.m., say, then fast until lunch the next day. (Noncaloric beverages like coffee and water are OK.) By limiting the amount of time you eat every day, you may naturally take in fewer daily calories, Smith says. Fasting can kick your body into burning stored fat and provide other metabolic benefits that may boost longevity.

Does it work? To date, most of the research into fasting for weight loss has been done with animals. In humans, the evidence is mixed: One 2018 study published in the journal Nutrition and Healthy Aging found following a 16/8 regimen for three months decreased body weight by about 3 percent. But a 2020 human study in JAMA Internal Medicine showed little weight loss benefit: Overweight adults assigned to fast for 16 hours a day for three months lost only two or three pounds — much of it healthy muscle mass, not body fat.

The downsides: Not eating for long periods takes lots of willpower and can be hard to stick with over the long haul. “Fasting can foster an unhealthy attitude toward food. You are not learning to listen to your natural hunger cues, which is important for maintaining a healthy relationship with food,” Smith says. Fasting is not safe for people with prediabetes, diabetes or a history of disordered eating, she adds.

What to steal: Don't nosh around the clock. Deciding the kitchen is closed after dinner can prevent mindless midnight munching. “Giving yourself a natural 12-hour break allows your body to get into healing and maintenance mode while you sleep instead of putting energy into digesting,” Cassetty says.

Whole30

Whole30 is a one-month dietary reboot. For 30 days, you eat only a limited menu of whole foods — meat, seafood, eggs, fruit and veggies, and natural fats like olive oil, nuts and seeds. You can't have added sugars, artificial sweeteners, alcohol, grains, legumes, dairy or junk foods, which, the thinking goes, may be triggering inflammation and allergies. This cold-turkey approach is designed to help you break your cravings and bad food habits, and begin with a clean slate. In the process, you may lose some pounds as well. After the 30 days, you slowly reintroduce the excluded foods to your diet and see how each makes you feel.

Does it work? Personal testimonials abound on Instagram and elsewhere. “But I don't know of any scientific research behind this diet. It wasn't created by a credentialed expert,” Cassetty says.

The downsides: “It is very restrictive,” says Amy Gorin, a registered dietitian in the New York City area and owner of Plant-Based Eats. “If you slip up and eat a bite of pizza, you have to start over. This type of unforgiving mentality doesn't work well with making lasting lifestyle changes.” You may risk nutritional deficiencies if you follow it longer than a month: “I don't recommend doing so,” Gorin says.

What to steal: Be more mindful. Though this scorched-earth approach may be extreme, experts say it can be useful to experiment with cutting back on potentially problematic categories like refined sugar or alcohol consumption. Do you sleep better or have more energy? “It can be helpful to examine eating habits you do mindlessly,” Cassetty says.