Knowing what to eat is much more complicated than simply looking at a food guide.

Take protein, for example.

When the Atkins diet was trending, protein was hailed as the macronutrient everyone needed more of. We were told to eat more protein and fewer carbohydrates.

Then, with the rise of plant-based diets, our understanding of protein shifted yet again. Suddenly it was said that we were eating too much protein, and that protein from animal sources was a culprit in a whole host of health issues: osteoporosis, kidney disease, calcium stones in the urinary tract, and even some cancers.

Some doctors — such as Canadian cardiologist Dr. Shane Williams — even began prescribing a plant-based, lower protein diet for those trying to improve their health and lose weight.

And now? We may be back to protein, at least early in the morning.

A new study argues that protein is a powerhouse macronutrient that should be eaten for breakfast in order to help curb afternoon sugar cravings.

Researchers also suggest that eating protein helps people feel satiated, meaning they’re less likely to overeat.

Seems like a surefire way to improve your health and commit to weight loss or management goals, no?

Well, we heard from nutritional experts to get their perspective on protein — and protein for breakfast in particular. Here’s what we learned.

Protein and weight loss

Tim Ferriss, a wellness advocate and New York Times best-selling author, argues that eating the right breakfast can help someone lose a significant amount of weight.

“If you nail breakfast, even if you don’t change any of your other behaviors, that is often enough to lose 10 to 20 pounds per month of fat… Fat loss is 99 percent diet,” Ferriss says in one of his wellness videos.

His ideal breakfast is based on a 30/30 plan: Eating 30 grams of protein within 30 minutes of waking up.

We talked to Kristin Kirkpatrick, MS, RD, LD, a licensed, registered dietitian, wellness manager at the Cleveland Clinic Wellness Institute, and author of the book “Skinny Liver.”

While she doesn’t have her patients follow the 30/30 rule, she agrees that eating protein for breakfast can help curb afternoon cravings and increase satiation, thus improving weight loss or management goals.

“The old thinking was that you should eat within an hour of waking. But recent studies show that although breakfast is a key meal, and should be your largest, it does not have to be eaten immediately after waking. I tell my patients to listen to their hunger and to eat when their body tells them to — aiming for at least before 11 a.m. if possible,” Kirkpatrick told Healthline.

“Researchers believe that having protein early in the day at breakfast may help to control reward centers in the brain and brain signals that control food motivation that often cause you to want to indulge later on,” she added. “Protein has filling aspects that take away hunger and cause you to eat less.”

Mitzi Dulan, RD, founder of simplyFUEL, said that to experience the biggest benefits, protein consumption shouldn’t be confined to breakfast alone.

“Eating protein in the morning can help curb cravings, but you should also have protein at lunch, which helps curb the afternoon cravings,” Dulan told Healthline. “Eating regular meals throughout the day and starting that with protein can help you manage the weight.”

The best type of protein to eat

Protein, however, is a broad category that includes all the food groups.

So, what’s the best way to get your protein?

Ferris suggests a breakfast of eggs, lentils, black beans, and dark green vegetables.

Kirkpatrick said “both animal and plant can be high quality, but [I ask my] patients to avoid over-indulgence of processed meats such as bacon, sausage, etc.”

Dulan included greek yogurt and protein balls in her ideal protein-packed breakfast spread.

“You can eat a variety of protein in the morning. Eggs, greek yogurt, or protein balls would all be great options,” she said.

Can you consume too much?

Can there be too much of a good thing?

Is there an optimal number of grams of protein we should strive to consume at breakfast, as Ferris suggests?

Kirkpatrick assures us that there really isn’t a thing as too much protein, unless you have pre-existing kidney issues.

Overall, balance is key.

“If the goal is to have breakfast make up the bulk of your protein for the day, then you can tone it down with other meals later in the day as well,” she said.

Dulan suggests slightly less protein for breakfast than Ferris (20 grams instead of 30), but also adds that unless someone is eating spoonfuls of protein powder, overconsumption is likely a nonissue.