Hidden calorie trap: How ultraprocessed foods make you overeat without realizing it
By isabelle // 2025-07-31
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  • Ultraprocessed foods (UPFs) make up half of the average U.S. diet and cause people to unknowingly consume 500 extra calories daily, leading to weight gain and obesity.
  • Studies show UPFs bypass natural satiety signals, causing overeating without increased hunger, while their hyperpalatable ingredients trigger addictive cravings and disrupt gut health.
  • UPFs are engineered for fast consumption, suppressing hormones that regulate fullness and altering gut microbiota, contributing to metabolic dysfunction and insulin resistance.
  • A shocking 87% of baby snacks and 79% of infant cereals are ultraprocessed, misleading parents with "healthy" packaging while setting children up for lifelong obesity.
  • Experts urge stricter marketing bans and taxes on UPFs, citing global obesity rates doubling since 1980, as the industry profits from addiction and misinformation.
Why are millions of Americans unknowingly consuming hundreds of extra calories daily, leading to skyrocketing obesity rates? The answer lies in the deceptive nature of ultraprocessed foods (UPFs), which now make up half of the average U.S. diet. A groundbreaking study published in Cell Metabolism reveals that participants consuming UPFs ate 500 extra calories per day—without even realizing it—compared to whole-food diets with identical nutrients. Nutritional epidemiologist Filippa Juul, a leading researcher at SUNY Downstate Health Sciences University, warns that UPFs are engineered to hijack appetite regulation, promote overeating, and set children up for a lifetime of metabolic dysfunction.

The hidden calorie trap

In 2019, Kevin Hall, a former NIH scientist, conducted a controlled feeding study at a Bethesda research hospital. Twenty participants spent two weeks on a UPF-heavy diet (featuring chips, candy, and packaged meals) and two weeks on a whole-food diet. Despite both diets being matched for calories and macronutrients, participants unconsciously consumed 500 extra calories daily on the UPF diet, leading to measurable weight gain. Shockingly, they didn’t report feeling hungrier or more satisfied, proving UPFs bypass natural satiety signals. A follow-up study in Japan replicated these findings, with UPF diets driving 800 extra calories per day compared to traditional meals. "This is the strongest evidence we have," Juul told U.S. Right to Know.

How UPFs sabotage your body

UPFs are designed to be hyperpalatable, loaded with industrial combinations of fat, salt, and sugar that trigger dopamine-driven cravings. But the damage goes deeper:
  • Faster eating, fewer signals: UPFs are often soft and easy to chew quickly, leading to faster calorie intake before the brain registers fullness.
  • Altered gut response: Nutrients in UPFs are absorbed earlier in the digestive tract, suppressing appetite-regulating hormones like GLP-1 that normally signal satiety.
  • Addictive engineering: Emulsifiers, synthetic sweeteners, and texture modifiers disrupt gut microbiota, linked to inflammation and insulin resistance.
Juul emphasizes that UPFs are not just "junk food"; they’re chemically altered products masquerading as food. Moreover, the food industry has essentially normalized eating anywhere and at any time using aggressive marketing tactics targeting children.

The baby food scandal

A University of Leeds study exposed that 87% of baby snacks and 79% of infant cereals are ultraprocessed. Dr. Diane Threapleton, the lead researcher, slammed these products for bearing "little resemblance to the kind of food young children should be growing up on" despite "healthy" packaging claims. The Obesity Health Alliance (OHA) condemned the industry for "flooding shelves" with sugary, addictive UPFs that set children up for a lifetime of obesity. Juul advocates for stricter marketing bans on UPFs, especially for children, and points to countries like Chile and Mexico, which imposed taxes on sugary drinks and junk food. With obesity rates doubling globally since 1980, the evidence is clear: UPFs are a public health emergency. Unfortunately, the UPF industry profits by keeping consumers addicted and uninformed. Until regulators crack down on deceptive marketing and restore real food to diets, the obesity crisis will only worsen. Sources for this article include: ChildrensHealthDefense.org Independent.co.uk Nature.com
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