This new diet says some 'healthy' foods might actually make you GAIN weight

In his new book, The Plant Paradox, Steven Gundry, M.D., a cardiologist and heart surgeon based in Southern California, claims that the worst food for weight loss is any food containing a plant protein called lectin. But here's the thing about lectins: They're found in foods you’ve always thought were good for weight loss. Think: whole grains, beans, nightshade vegetables (eggplant, potatoes, tomatoes, peppers, squash), legumes, nuts, seeds, dairy, and any animal protein that's not pasture-raised (eggs, meat, poultry).

Gundry claims that humans weren't intended to eat foods containing lectins and that eliminating those foods can decrease inflammation, boost weight loss, and lead to an overall healthier lifestyle. But is this really legit? We talked to Gundry and a few experts to find out.

Lectins are essentially a plant's defense mechanism against predators, Gundry says. As a result, they trigger an inflammatory response once consumed that can lead to weight gain and other serious health conditions, such as leaky gut and irritable bowel syndrome (IBS), he says.

Gundry also points out that traditionally grains and beans have been used to fatten up animals before slaughter. So it only makes sense that consuming lectin-rich foods would fatten up humans, as well. Gundry says that he's personally lost 70 pounds on a lectin-free diet, and that he's put many of his patients on this plan as well. “The amazing thing is when people change nothing except removing major lectins, they start losing weight and they still are eating lots of calories, but we’re not storing it as fat anymore,” Gundry says.

He also cites a 2006 study that indicates that a lectin-free diet can have a positive effect on people with cardiovascular disease and metabolic syndrome (a group of conditions indicated by increased blood pressure, high blood-sugar levels, excess body fat around the waist, and abnormal cholesterol levels).

Anytime you eliminate certain foods without replacing them with other products, it's highly likely that your overall calorie intake will decrease. But that doesn’t mean that cutting out lectin-containing foods will automatically lead to weight loss, says Leah Kaufman, R.D. In order for successful weight loss to occur, you need to follow a well-balanced diet (that means including some lectin-containing foods) and burn more calories than you take in, says Kaufman.

Plus, most foods with lectins can be super beneficial for weight loss, says Samantha Cassetty, R.D. For example, one 2017 study published in the American Journal of Clinical Nutrition linked whole grains with weight loss. And another study published in the same journal found that people who consumed pulses over a six-week period (a.k.a. beans, lentils, chickpeas) lost significantly more weight than those who didn't consume any pulses. Should You Try It?

That being said, Kaufman has seen weight-loss success in patients with IBS through eliminating certain lectin-containing foods via a low FODMAP diet, which cuts out foods like beans and starchy vegetables.

For an average person sans-dietary restrictions or stomach problems, Kaufman recommends a diet focused on reasonable portions of all food groups. She recommends aiming to make one-quarter of your plate carbs, one-quarter lean protein (regardless of how it was raised), and then filling the rest of your plate with any kind of vegetables you like.

The bottom line: Certain foods, no matter how healthy, affect people differently. Sure, a lectin-free diet could help you lose weight. But unless you struggle with digestion issues, you're probably better off sticking to a diet that's easier to follow for the long run. After all, that's what leads to weight loss that lasts.