Some foods are easy to categorize as good or bad. For instance, if you want to be slim and healthy, you know you need salmon and kale on your team, not doughnuts and pizza.

But sometimes, things aren’t so simple. In fact, there’s one group of foods I think of as frenemies—sometimes friends, sometimes enemies— because they can be either good or bad for you. Recently, on Dr. Oz, I talked about one of these frenemies: NUTS. Here’s a look at their pros and cons.

What’s good about nuts?

In lots of ways, nuts are a fabulous food. For instance, they’re rich in healthy omega-3 fatty acids. They’re also nutrient-dense, giving you a hefty dose of vitamin E, B vitamins, minerals, and fiber What’s more, they can lower your cholesterol.

In addition, nuts are handy. You can throw a bag of them in your lunch box, keep a can in your desk drawer at work, or simply toss some on a salad at dinnertime.

So nuts have a lot going for them. But now let’s look at the flip side.

What’s bad about nuts?

There are a number of reasons why nuts are on my frenemies list. For instance:

• While they’re rich in anti-inflammatory omega-3 fatty acids, they’re also high in pro-inflammatory omega-6 fatty acids. It’s the ratio of these that’s crucial, and this ratio isn’t great in nuts.  As a result, a diet high in nuts could contribute to the inflammation that underlies everything from cancer to obesity.
  
• Many people—especially those with autoimmune problems—are highly sensitive to nuts.
  

These alone are good reasons to limit your nut intake (or possibly avoid nuts altogether, if you have an autoimmune problem). But I actually have a much bigger beef with nuts. The problem is that they’re SO DARNED GOOD.

Here’s the thing. Nuts are fine when we eat them in small quantities. But that’s not what we typically do. They’re so crunchy and delicious that we say, “I’m just going to have a handful,” and then we wind up scarfing down a whole bowl of them. As I said on Dr. Oz, we become human nut vacuums.

I’ve guided weight-loss transformations for more than two decades, and it’s amazing how many diets go off the rails because of nuts. When my patients say, “I’m trying so hard but the numbers on the scale aren’t dropping,” I usually find when we dig deeper that nuts are the biggest culprit. And when we cut down on those nuts, people start to get results.

Dr. Kellyann talks with Dr. Oz about The Great Nut Debate from Kellyann Petrucci on Vimeo.

How to add nuts to your diet?

If you love nuts, there’s an easy way to enjoy their benefits while avoiding their drawbacks. Simply allow yourself ONE CLOSED HANDFUL PER DAY at most. (That’s around 18 to 24 nuts.) That way, you’ll get the rich nutrition and crunchy goodness of nuts without packing on pounds or overloading yourself with omega-6 fatty acids.

The key here is to be really strict when you measure that handful—no cheating! People get into trouble when “portion creep” sets in, and a closed handful of nuts gradually turns into an open handful. This may not seem like a big deal, but those calories add up fast. So if you can’t close your hand, put some of those nuts back in the bowl for tomorrow.

There you have it: a simple solution to the nut problem. Follow the “closed handful” rule, and stick to a maximum of one serving of nuts per day.  And just like that, you can transform this fun food from a frenemy into a full-fledged friend!