The latest food fads promise weight loss, more energy, and better all-around health. But do they deliver?

By Juno DeMelo
Happy Asian family preparing food in the kitchen
Credit: bearinmind/Shutterstock

You'll hear it whether you're at the gym or in a nice restaurant: At least one person talking about her new healthy eating plan and how great it's making her feel. Intrigued, you consider getting on board—and bringing your family along for the ride. Here's what you need to know about the most popular diets before you make the leap.

1. Paleo Diet

What it is: Named for the Paleolithic era, Paleo emphasizes what hunter-gatherers supposedly ate—animal proteins, fresh fruits and veggies, and nuts and seeds—and banishes grains, legumes, dairy, and white sugar.

The pros: Paleo encourages eating fewer processed and packaged foods in favor of whole ones.

The cons: "Because this diet declares nutritious foods off-limits and allows unrefined sweeteners, like maple syrup, but not refined ones, it can be very confusing for kids," says Willow Jarosh, R.D.N., who cofounded C&J Nutrition in New York City with fellow mom and registered dietitian nutritionist Stephanie Clarke. "And the heavy emphasis on protein at the expense of higher-fiber foods can result in a lack of adequate daily fiber intake."

The bottom line: If you're tempted to try it, choose top-quality animal protein from grass­fed, organic sources. And while it's fine to try to get your little ones to cut back on macaroni and cheese, pizza, and sugary breakfast cereal, experts don't recommend eliminating entire food groups from kids' diets.

2. Ketogenic (Keto) Diet

What it is: A high-fat, ultra-low-carb plan that purports to force your body to rely on fat instead of carbohydrates for fuel, a state called ketosis. Expect to eat a lot of meat, full-fat dairy, and non-starchy vegetables.

The pros: You'll probably lose weight, at least in the short term.

The cons: Keto diets can be used to help control seizures in children with epilepsy. "But otherwise, I would not recommend this diet," says Stephanie Middleberg, R.D., the founder of Middleberg Nutrition in New York City, the author of The Big Book of Organic Baby Food, and a mother of two. "Certain fruits and veggies are off the table, which can lead to constipation and deficiencies in vitamins and minerals such as vitamin D, copper, and zinc. And given the high fat component, cholesterol levels can also become elevated."

The bottom line: Unless this diet is medically necessary and you're working with a medical or nutrition professional, skip it.

3. Whole30

What it is: You'll cut out all sweeteners, alcohol, grains, legumes, and dairy for—you guessed it!—30 days in an effort to "reset" your palate, metabolism, and digestion.

The pros: You don't count calories or weigh yourself, and there are tons of websites and recipes out there to help you stick to the plan, which encourages consuming a variety of fruits and vegetables. "And this diet is an excellent choice for anyone having tummy troubles they can't put their finger on," says Middleberg. "Eliminating the majority of GI triggers for 30 days before reintroducing them can be useful to see what's causing pain."

The cons: Like the keto and Paleo diet, Whole30 is also restrictive.

The bottom line: "It's really difficult to keep the dialogue around food positivity when entire food groups are off limits, especially when you're cutting them out to lose weight," warns Jarosh. "We don't suggest parents go on restrictive diets, including Whole30, if they have kids who will be eating the same meals as they do."

4. Vegan Diet

What it is: Vegans avoid all animal products, including meat (obviously), poultry, seafood, eggs, dairy, and honey.

The pros: Research shows this high-fiber diet may help reduce your risk of heart disease and diabetes.

The cons: It'll take some careful planning to make sure you're getting enough calcium, vitamin D and B12, omega-3 fatty acids, iron, and zinc.

The bottom line: "If your family wants to cut out animal products for ethical or religious reasons, we recommend seeing a registered dietitian to help plan a vegan diet, which can be challenging for children, who tend to go through picky eating phases," says Jarosh.

5. Mediterranean Diet

What it is: Though people in Mediterranean countries don't all eat the exact same thing, their diets do emphasize whole grains, fruits and vegetables, nuts, and healthy fats, plus seafood at least twice a week and moderate amounts of poultry, eggs, and dairy.

The pros: This diet's really more of an eating pattern than a structured plan, which makes it easy to stick to over time. And studies show it's associated with a reduced risk of heart disease, cancer, and overall mortality.

The cons: None!

The bottom line: Because this "diet" limits certain foods without declaring them bad or off-limits, experts say it's the one most likely to lead to your kids having a positive relationship with food. It also ensures that your child is getting enough nutrients and makes meal planning relatively easy, says Middleberg. Bon appétit!