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Why eating ultra-processed food makes us overweight

Scientists warn that 57 percent of adult Americans' energy intake now comes from ultra-processed foods.

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By Alice Clifford via SWNS

Eating ultra-processed junk food like sausages and candy makes us overweight by decreasing
the amount of energy gained from your diet, scientists have revealed.

Consuming these unhealthy foods can lead to dietary protein dilution, meaning the protein in people’s diets provides less energy than from other, healthier foods.

This dilution has contributed to the obesity epidemic as to get the necessary amount of protein the body needs, people must eat more food, such as carbs.

Scientists warn that 57 percent of adult Americans' energy intake now comes from ultra-processed food.

As well as ultra-processed foods, the researchers also looked at discretionary foods.

These are foods that are high in added sugar, saturated fats, added salt or alcohol, and are often highly processed.

The team used an approach called nutritional geometry to detect complex nutritional associations in diets.

fried chicken nuggets
Eating junk foods such as chicken nuggets decreases the amount of energy gained from your diet. (Chatham172 via Shutterstock)

This method allows multiple components to be observed at the same time, letting researchers observe how nutrients interact, as when one nutrient changes, others change as a consequence.

They divided people into five equal groups, depending on how many processed foods they ate daily. The bottom 20 percent ate the least and the top 20 percent ate the most.

After assessing how much ultra-processed and discretionary foods people ate, they found that ultra-processed foods contributed to 57.2 percent of people’s average daily energy intake, while discretionary foods contributed to 44.5 percent.

The study found that those who ate the most ultra-processed foods consumed 445 calories more non-protein energy than those who ate the least, consequently leading to weight gain.

Also, the proportion of energy people gained from protein decreased.

Those who ate the least of these processed foods gained 18.7 percent of energy from protein while those who ate the most gained 12.4 percent of energy from protein.

Their energy intake also rose by 552 calories, once more contributing to weight gain.

The researchers also looked at how these foods affected body mass index, (BMI). They found that the more ultra-processed or discretionary foods people ate, the higher their BMI was.

They revealed that the average BMI of people who ate the least discretionary foods was 28.4, while those who ate the most reached 29.9.

This was also true with people who consumed more ultra-processed foods. Those who ate the most had an average BMI of 30.5, while those who ate the least had a score of 27.8.

Dr. Amanda Grech, a nutrition epidemiologist and accredited practicing dietitian working as a research fellow at the University of Sydney, and co-author of the study, said: “Foods that we would describe as unhealthy, whether termed discretionary foods or ultra-processed foods, comprise a substantial proportion of energy intake and increased intake results in protein dilution in the diet and higher energy intakes.

“Increasing discretionary food consumption was associated with a higher absolute energy intake compared with increasing UPF consumption while increasing ultra-processed food consumption was associated with a larger increase BMI compared with increased discretionary food consumption.

“However both increased ultra-processed food consumption and increased discretionary food consumption are associated with overweight/obesity and interventions to improve dietary patterns are critical.”

Despite people having varying diets, the study found that people consume a fixed target of protein each day.

Dr. Grech says: “In this study, we found that regardless of how much discretionary food or ultra-processed foods was consumed, participants consumed 1400 kJ (334 calories) of protein.

“The consequence of trying to achieve our protein target each day is that we overconsume carbohydrates and fats when the foods we consume are ‘protein diluted’ in order to achieve this, elevating total energy intake.”

Yet while the best thing for our health is to avoid eating too many ultra-processed foods and discretionary food, it is easier said than done.

Dr. Grech said: “We should avoid foods with cheap fats, sugars and refined starches with lots of colorings, flavorings and artificial preservatives - these are ultra-processed foods and include foods such as ready meals, commercial breads, processed meats, fast foods, confectionary and snack foods.

“Instead we need to replace them with minimally processed foods including fruits, vegetables, wholegrains and lean sources of protein such as fish, legumes, eggs, whole nuts or poultry and small amounts of dairy products.”

The research was presented at this year’s International Congress on Obesity in Melbourne, the biennial congress of the World Obesity Federation.

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