Ultra-processed foods push teens to eat more even without hunger, scientists warn

Those familiar crisps, flavoured yoghurts and ready-meals, are a favourite among many youngsters aged between 18-21. A  recent research suggests that late adolescence may be a uniquely sensitive time, where what you eat can impact not just your weight, but your instincts around hunger itself.

Piecing together an unsettling story about ultra-processed foods, a team of researchers at Virginia Tech has revealed that these foods may affect younger adults differently from their slightly older peers. While previous studies hinted at links between such foods and weight gain, this new work homes in on a subtle yet alarming pattern, which reveals that even when daily calories were tightly controlled, 18- to 21-year-olds still ate more at a buffet meal after two weeks on an ultra-processed diet. More troubling still, they continued snacking when they were no longer hungry, a well-established predictor of future weight gain.

These findings point towards wider concerns about a generation already facing rising obesity rates. A recent analysis in The Lancet predicts that by 2050, one in three Americans aged 15 to 24 will meet clinical criteria for obesity. Although genetics and sedentary lifestyles play their part, diet sits at the centre of the issue. Young people in the US get as much as 65 percent of their daily intake from ultra-processed foods, items laden with additives, engineered flavours and industrial ingredients far removed from anything a home cook might recognise.

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What the study says

A vulnerable age window

Late adolescence, especially between 18 and 21, appears to be a period when food choices exert outsized influence. Participants in this group ate significantly more after an ultra-processed diet, while those aged 22 to 25 did not show the same rise.

Eating beyond hunger

After finishing a substantial buffet meal, younger participants continued eating snacks even after they reported no hunger. This behaviour intensified following the ultra-processed diet and is considered a strong predictor of later weight gain.

Controlled diets, clear differences

The researchers matched the two diets, one ultra-processed, one not, across 22 nutritional characteristics, from macronutrients to fibre and vitamins. This careful design ensured that the only major difference was the level of processing.

The NOVA classification

Foods were categorised using the NOVA system, a framework developed in Brazil that groups foods by their degree of processing. Ultra-processed items include soft drinks, flavoured yoghurts and most packaged snacks, foods that dominated the high-processing diet.

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A buffet reveals hidden effects

Participants arrived fasting and were offered 1,800 calories’ worth of breakfast foods. Only the youngest group increased their intake after the ultra-processed phase, demonstrating a specific sensitivity.

Though the study lasted just two weeks per diet, the results suggest that prolonged exposure could shape long-term habits. Researchers emphasise that daily life, with constant access to snacks, might amplify these effects. Scientists plan to widen the study with younger participants, longer trial periods, and tools such as brain imaging to uncover why ultra-processed foods exert such a pull on teens and young adults.

FAQs on Health Risks of Ultra-processed Foods

1. What are ultra-processed foods?

Ultra-processed foods include items like crisps, flavoured yoghurts, and ready meals. These foods contain additives and engineered flavours, and are made with industrial ingredients not typically found in homemade food.