Following the 30/10 rule could help you eat more protein and make meals healthier, according to a dietitian

• The 30/10 rule involves getting 30 grams of protein and 10 grams of fiber at each meal.
• A dietitian said it's legit, and the advice could help you build muscle and cut back on junk food.

You don't have to overhaul your diet if you want to build muscle, burn fat, or just eat a little healthier — a simple tweak can help you get more nutrients to meet your goals.

The 30/10 rule is a healthy-eating hack circulating online (health journalist Michael Easter's newsletter recently attributed it to Michael Roussell, who has a PhD in nutrition science).

To follow it, all you need to do is get 30 grams of protein and 10 grams of fiber in each meal: breakfast, lunch, and dinner.

While the 30/10 rule isn't foolproof, it could be a helpful step in eating healthier by focusing on major macronutrients like protein without overly complicating your diet, according to registered dietitian Brierley Horton.

"The concept of it is fascinating to me, and the idea of breaking your diet down into macros is very popular," she told Insider. "There's tons of research to talk about the benefits of both protein and fiber, and even specifically in those amounts.

The simplicity of the rule, and its foundation in good evidence, could make it useful for people looking to build lean muscle, manage their weight, or cut back on processed foods.

Eating enough protein can help build muscle and prevent hunger

Protein is an important nutrient for repairing tissue, helping muscles grow back bigger and stronger after exercise.

"We know that adding protein to your diet helps you build muscle," Horton said.

Research suggests at least 1.5 grams of protein per kilogram of bodyweight (or 0.7 grams per pound) is an ideal amount of protein to build muscle and strength. That works out to 98 grams of protein per day for a 140 pound person. The 30/10 rule with three meals a day at 30 grams of protein each gets you nearly to the goal at 90 grams per day.

As a result, the 30/10 rule could help active people get enough protein, Horton said.

The rule could also be helpful for people with blood sugar issues, including perimenopausal women, since protein and fiber help regulate how quickly carbohydrates are digested and how much blood sugar rises as a result, according to Horton.

"Doubling down on protein while getting that fiber could be really helpful," she said.

One caveat about the 30/10 rule, however, is that it may not be a good idea to rely too much on protein shakes or bars to hit those numbers, Horton said. Supplements can be helpful, but can't replace all the benefits of whole food protein sources.

"There's so much nutrition in protein-rich foods like dairy products, fish, poultry, and even red meat," she said. "You get a synergistic effect from the other nutrients in those foods."

Horton recommended an example of a high-protein recipe that fits the 30/10 rule with whole foods in the form of taco quinoa bowls.

Getting enough fiber improves digestion and reduces disease risk

Fiber is a type of carbohydrate that helps feed healthy bacteria in the digestive system, slows the absorption of sugars, and may help prevent chronic illnesses like cancer and heart disease.

Many people don't get enough fiber, and the typical recommendation is between 25 to 38 grams per day, so the 30/10 rule is on track with 30 grams (not including any snacks).

Focusing on protein and fiber in each meal can also help you cut back on less nutritious foods such as ultra-processed foods that are lacking in both, which can be a benefit if you're looking to manage your weight while adding muscle.

"There's not a lot of room for a lot of extra," Horton said. "That's something that would help with building lean muscle."

The 30/10 rule also encourages adding more beans to your diet, Horton said. Beans pack both fiber and protein, and some experts even consider them a cheap and versatile superfood for longevity.

As with your protein sources, Horton added that it's a good idea to aim for mostly whole foods to get your fiber. There's no calorie recommendation with the 30/10 rule, so if you're over-relying on supplements, it's still possible to have an unbalanced diet, she said.

Be careful to get enough variety in your diet

One potential downside of the 30/10 diet is that focusing on hitting those numbers could make it tempting to eat the same foods over and over again, which can put you at risk of missing out on some key nutrients.

"Over time, you might start to lack diversity," Horton said.

She added that it's important to "eat the rainbow" to get plenty of plant-based compounds called phytochemicals which have tons of health benefits including reduced risk of disease and lower inflammation.

"You can take a multivitamin to make up for some of those nutrients but you're not necessarily getting those phytochemicals, and that's something we shouldn't overlook," she said.

The 30/10 rule also isn't for everyone — Horton said it's likely to be too restrictive for kids, and people with digestive issues may need careful planning to handle the high doses of fiber without side effects.

Otherwise, there's no particular downside to the rule if you take reasonable precautions to eat a wide variety of mostly whole foods, and it could help simplify your meal planning.

"Everything fits in your diet, but moderation is key," she said. "I think it's most important to meet people where they're at."