Eating processed foods like pizza and chips can cause 'protein hunger' — fueling weight gain and overeating, study finds

Eating processed foods like pizza and chips can cause 'protein hunger' — fueling weight gain and overeating, study finds
Opting for lots of processed convenience foods, such as pizza, could lead you to get less protein in your diet and feel hungrier, potentially prompting overeating and weight gain.Oscar Wong/Getty Images
  • Processed foods may contribute to weight gain because they're low in protein, new research suggests.
  • A lack of protein may prompt the body to try to balance nutrients by overeating, researchers theorize.

Eating too many processed foods could deprive you of protein and potentially lead to weight gain, new research suggests.

Researchers from the University of Sydney, Australia, funded in part by a red meat marketing and research company, looked at data on the eating habits of 9,341 Australians, collected between 2011 and 2012 as part of a national nutrition survey.

They found people who "diluted" their diet with low-protein meals — particularly in the form of processed foods like pizza, chips, and fast food — tended to eat far more calories than they needed over the course of the day.

Conversely, the researchers found that participants whose first meal of the day was high in protein tended to eat less overall, which suggests getting a head-start on your protein needs for the day could curb appetite.

The researchers concluded our bodies may try to stimulate appetite when we're lacking protein, to compensate. The resulting "protein hunger" could drive us to overeat seemingly substantial processed foods, rather than vegetables and whole grains that are actually high in protein.


A protein-rich breakfast could help you eat less overall

The study, published November 2 in the journal Obesity, suggests that how much protein we eat could make a difference in our total calorie intake — and whether we can gain or lose weight.

The recommended protein intake is between 0.36 to 0.9 grams per pound of body weight per day.

The researchers theory suggests that our bodies aim to get within that range of protein — so if protein is a relatively small part of our diets, we have to eat a lot more to get enough.

A person who weighs 150 lbs would need between 54 to 135 grams of protein per day. Each gram of protein has around four calories, so that works out at about 216-540 calories a day of high-protein foods like meat, fish, chicken, Greek yogurt, beans, or soy.

If that person ate a diet that is 15% protein, they'd need to eat up to 3,600 calories total to get enough protein, which could contribute to weight gain.


In contrast, they'd be able to eat enough protein in up to 2,160 calories a day if their diet is 25% of daily calories from protein, keeping them well within the range recommended to maintain weight.

"The hypothesis is that we need a certain amount of protein to function, and we will keep eating till we get to [the right number]," obesity expert Giles Yeo, who was not involved in the study, told Insider. "The data supporting it is quite solid. Most of the work was first worked out in flies and mice, but increasing evidence from human studies indicate it occurs, at least under certain conditions, in humans as well."

Added protein and fiber can help, but don't neglect whole foods

Cutting out processed foods can be challenging, since they show up everywhere in our diet, and are cheap, convenient, and tasty. Some evidence even suggests the combination of refined carbohydrates and fats in processed foods can be addictive.

But it may be possible to make better choices with processed foods by opting for versions with more protein and fiber, and less added sugar, fat, and salt, Yeo previously told Insider.

Doing so may help you feel full for longer, and help prevent overeating typically linked to processed foods.


However, too many processed foods of any variety can crowd out whole foods like fruits, vegetables, whole grains, and legumes in your diet, which are an important source of vitamins and minerals.

As a result, it's important to think about the overall context of what you eat, not just specific nutrients, according to Yeo.

"We eat food, not calories," he said.