In response to the body’s intense craving for protein, people who regularly eat ultra-processed foods tend to overeat, as shown in a new study. A one-year study of the eating habits of 9,341 Australians lends credence to the theory that an increase in the consumption of highly processed and refined foods is a major factor in the current epidemic of obesity in the Western world.
The new research provides additional support for the ‘Protein Leverage Hypothesis,’ and it was based on data from a nationwide survey of Australians’ diets and levels of physical activity. It was carried out by the Charles Perkins Centre (CPC) at the University of Sydney and featured in the current issue of Obesity. The Protein Leverage Hypothesis was first proposed in 2005 by professors Raubenheimer and Stephen Simpson. It proposes that people tend to eat too much fat and carbohydrates because their bodies have an insatiable craving for protein. These days, most people eat highly processed and refined foods, which are lacking in protein. To make up for this, they eat more energy-dense foods.
People’s protein intake decreases as they eat more processed and refined foods, increasing their risk of obesity and the chronic diseases that come with it. It’s becoming more and more obvious that eating is primarily motivated by a need to satiate a protein targe. But there’s a problem: protein content in Western diets is falling. As a result, you’ll need to eat more of it to meet your protein goal, which will increase your calorie consumption.
Proteins are essential for the survival of all living things; they can be found in every cell of the body and are used to either repair damaged cells or create entirely new ones. It is approximated that over a million different types of proteins are required for a human body to function normally.
What did the study investigate?
Researchers at the University of Sydney analyzed data from the National Nutrition and Physical Activity Survey, a cross-sectional survey of diet and exercise habits among 9,341 adults aged 46 years and older that was conducted between May 2011 and June 2012. The average daily energy intake was calculated to be 8,671 kilojoules (kJ), with 18.4 percent coming from protein, 43.5 percent from carbohydrates, 30.9 percent from fat, 2.2% from fiber, and 4.3% from alcohol.
The researchers did a plot of energy intake versus time of consumption and found that it followed the timing anticipated by the Protein Leverage Hypothesis. One study found that people who ate less protein at their first meal of the day ate more at subsequent meals, while those who ate the suggested amount of protein actually ate less. Furthermore, by the third meal of the day, they noticed a statistically significant distinction between the groups: those who started the day with a higher percentage of energy from protein consumed significantly less overall calories. Those who started the day with low-protein foods continued the trend, suggesting they were trying to make up for it by eating more. It’s worth noting that the first meal was the lightest in terms of energy and food ingested for both groups, while the final meal was the largest.
Participants whose first meal contained a lower protein proportion than recommended ate fewer of the suggested five food groups and more treats during the day. Therefore, they ate less protein at each meal and consumed more fats and carbohydrates, a phenomenon known as “protein dilution,” according to the researchers.
The findings lend credence to an ecologically and mechanistically cohesive theory of obesity in which a nutrient imbalance driven by a preponderant appetite for protein causes people to consume more calories from low-protein, highly processed foods.
