Unfortunately for these teens, a new study from health researchers in Turkey has found that free versions of all five of the most commonly used AI models will consistently recommend meal plans so low in calories and essential nutrients that following them can literally stunt their growth. What’s worse, for these teens, two independent registered dietitians who reviewed the researchers’ reported results for Gizmodo both agreed.
“Adolescence is one of the biggest periods of growth after infancy,” registered dietitian Taiya Bach tells Gizmodo. “They need far more calories than an adult.”
“Even if you’re overweight, you still have that growth component,” advised Bach, a member of the teaching faculty in the Department of Nutritional Sciences at the University of Wisconsin-Madison, “because a large portion of your calories are still going to hormones and growth and bone development.”
An incredible virtual nutritionist
The researchers behind the new study—Ayse Betul Bilen, assistant professor of health sciences at Istanbul Atlas University in Turkey—and her coauthors asked five free AI tools to create three-day meal plans for four hypothetical teenagers. All five bots, ChatGPT 4, Gemini 2.5 Pro, Bing Chat-5GPT, Cloud 4.1, and Perplexity, were given prompts that included information about the age, height, and weight of relatively average teens who were supposed to guide these meal plans.
Briefly, the instructions were to create a daily diet plan that included three meals and two snacks per day for four hypothetical 15-year-old children. Those four teens included a boy and a girl whose measurements would place them within the “overweight” percentile based on established body mass index (BMI) calculations, and another boy and girl falling into the “obese” percentile based on those same BMI metrics.
“We saw variability,” Bilen told Gizmodo, referring to the 60 daily diet plans provided by the chatbots. “However, despite this variation, many models showed similar overall patterns, such as underestimating total energy intake and altering the balance of macronutrients.”
Billen and his colleagues found that these AI models appeared to regularly err in the direction of higher protein intake, about 20 grams more protein than a professional dietitian recommended. AI also leans towards an almost ketogenic style of diet plan, which generally suggests a much higher intake of fat than that proposed by most sensitive dietitians with experience as carbon-based life forms.
The results were published Thursday in the journal leader in nutritionDozens of daily meal plans have been suggested in which approximately 21 to 24% of an adolescent’s energy needs would come from breaking down proteins and 41 to 45% would come from breaking down lipids.
Chatbots typically recommend about 115 grams fewer carbohydrates than a dietitian, resulting in a reduction of about 700 calories per day – the equivalent of skipping an entire meal every 24 hours.
Bad for sporty teens, bad for sedentary teens
Sotiria Everett, a registered dietitian and clinical associate professor at the Renaissance School of Medicine at Stony Brook University in New York, told Gizmodo that such drastic calorie restrictions and the risk of nutrient imbalances will only increase for student athletes.
“Low calorie intake can disrupt hormonal balance, potentially contributing to issues such as primary or secondary amenorrhea – in which the menstrual cycle is delayed or missed – in female athletes,” Everett explained via email. This calorie deficit, they wrote, can suppress the body’s natural production of both testosterone, the primary male sex hormone, and estradiol, the primary female sex hormone.
But according to Everett, the risks got worse from there. “In athletes, chronically low calorie intake can reduce energy availability and lead to a condition called Relative Energy Deficiency Syndrome (RED-S), a condition associated with increased injury and fracture risk, poor athletic performance, and delayed puberty depending on age,” he added.
And according to Bach, less physically active teens will still be at risk for bone fractures, stunted growth potential, and deficiencies in key micronutrients like carbohydrates.
“Basically, you need carbs to get taller. Like, you need it for linear growth,” Bach explained. “So, if you don’t have enough carbs, you can impact your height ability.” (This should be serious news to the small army of “luxmaxers” and other young people obsessed with any and all technical fraud to increase their height.)
While Bach cautioned that low-carb ketogenic diets have shown promise in helping individuals struggling with seizures and epilepsy, those diets have largely worked in close coordination with medical experts.
“It’s very strict,” she said. “And it’s that way for a reason, because it can be a little dangerous if you’re doing it yourself without thinking.”
“The way the body processes ketones leads to kidney stone risk,” Bach said, “and to a certain extent, too much protein can affect your bone health, because it messes with your vitamin D and calcium absorption — which is a concern anyway when you’re growing.”
Bach hopes the new study may lead to more research and more nuanced skepticism toward information generated by AI chatbots in general. “I do a lot of teaching and using AI at the college level, it’s huge,” she said. “There are a lot of errors there.”
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