According to Gram Research analysis, ultra-processed foods make up about 27% of what teenagers eat daily, and eating more of these foods is linked to consuming significantly more sugar and unhealthy fats, even though standard diet quality measurements don’t always catch this problem. A 2026 cross-sectional study of 338 Turkish adolescents found that teens eating the most junk food consumed substantially higher amounts of added sugars and saturated fat compared to those eating the least, with effects on body weight appearing more pronounced in boys.
A new study of 338 teenagers in Turkey found that ultra-processed foods like packaged snacks and fast food make up nearly 27% of what teens eat each day. Researchers discovered that eating more of these foods was linked to consuming too much sugar, unhealthy fat, and salt, even though the teens’ overall diet quality scores didn’t look that bad on paper. Interestingly, knowing about nutrition didn’t seem to help teens eat better. The findings suggest that current tools for measuring diet quality might miss the real damage that junk food does to teen health.
Key Statistics
A 2026 cross-sectional study of 338 Turkish high school students found that ultra-processed foods accounted for 26.98% of adolescents’ total daily energy intake, with the highest consumers eating more than 35% of their calories from these foods.
Teens in the highest ultra-processed food consumption group consumed significantly more total fat, saturated fat, and added sugars compared to those in the lowest consumption group, according to the 2026 study of 338 adolescents.
Among male adolescents in the 2026 study of 338 teens, body mass index-for-age z-scores differed significantly across ultra-processed food consumption levels, suggesting that junk food consumption may affect boys’ body weight more noticeably than girls’ at this age.
A 2026 analysis of 338 adolescents found no significant association between nutritional literacy and ultra-processed food consumption, indicating that nutrition knowledge alone may not prevent teens from eating processed foods.
The Quick Take
- What they studied: How much ultra-processed food (junk food) teenagers eat, whether it affects their diet quality, and if knowing about nutrition helps them make better food choices.
- Who participated: 338 high school students aged 13-17 years old from Eastern Turkey. Researchers measured their height and weight and asked them detailed questions about what they eat.
- Key finding: Ultra-processed foods made up about 27% of teens’ daily calories. Teens eating the most junk food consumed significantly more sugar, unhealthy fats, and salt compared to those eating the least. Surprisingly, this didn’t show up as a major problem in overall diet quality scores.
- What it means for you: Even if your overall diet looks okay on paper, eating lots of packaged and fast foods is still adding too much sugar and unhealthy fat to your diet. Knowing about nutrition facts alone may not be enough to help you make better choices: you might need practical strategies and support.
The Research Details
This was a cross-sectional study, which means researchers took a snapshot of 338 teenagers at one point in time rather than following them over months or years. Each student filled out a detailed food questionnaire describing everything they ate, answered questions about their background and family, and completed a test measuring their nutrition knowledge. Researchers also measured each teen’s height and weight to calculate their body mass index (BMI).
The scientists used a system called NOVA to classify foods as ultra-processed or not. Ultra-processed foods are products that have been heavily manufactured with added sugars, unhealthy oils, salt, and chemicals, think packaged snacks, sugary drinks, fast food, and instant noodles. They used a scoring system called the Healthy Eating Index to rate how good each teen’s overall diet was, looking at things like vegetable intake, whole grains, and added sugars.
This approach allowed researchers to see connections between how much junk food teens ate and their nutrition knowledge, diet quality, and body measurements, all at the same time.
Cross-sectional studies are useful for identifying patterns and connections in real-world situations. This design was appropriate because it allowed researchers to look at a large group of teenagers and see how their junk food consumption related to multiple factors like nutrition knowledge and body weight. However, this type of study can’t prove that junk food causes problems: it can only show that they happen together.
The study included a reasonable sample size (338 teens) and used established, validated tools for measuring diet quality and nutrition knowledge. The researchers collected actual measurements of height and weight rather than relying on self-reporting. However, because this is a cross-sectional study, it shows associations but not cause-and-effect relationships. The study was conducted in one region of Turkey, so results may not apply equally to all teenagers worldwide. Additionally, the study relied on teens’ memory of what they ate, which can be inaccurate.
What the Results Show
Ultra-processed foods accounted for 26.98% of the total daily calories that teenagers consumed, roughly one-quarter of their entire diet. When researchers compared teens eating the least junk food (bottom 25%) to those eating the most (top 25%), they found striking differences in nutrient intake. Teens in the highest junk food group consumed significantly more total fat, saturated fat (the unhealthy kind), and added sugars. They also consumed more B vitamins and calcium, likely because these nutrients are added to processed foods during manufacturing.
Surprisingly, when researchers looked at overall diet quality scores using the Healthy Eating Index, they found no significant difference between teens eating lots of junk food and those eating less. This was unexpected and suggests that standard diet quality measurements might not fully capture the problems caused by ultra-processed foods. Similarly, teens’ knowledge about nutrition (their nutritional literacy) didn’t show a clear connection to how much junk food they ate, meaning that knowing about nutrition facts didn’t necessarily help teens avoid processed foods.
When examining body measurements, most indicators like overall BMI didn’t differ significantly across the groups. However, one notable exception emerged: among male adolescents specifically, BMI-for-age z-scores (a measurement that accounts for age and growth) did differ significantly based on junk food consumption. This suggests that ultra-processed food consumption may affect boys’ body weight more noticeably than girls’ at this age.
The study revealed that ultra-processed foods are deeply embedded in adolescent diets, making up more than one-quarter of daily calories. The fact that teens eating more junk food consumed higher amounts of added sugars and unhealthy fats is concerning because these nutrients are linked to obesity, heart disease, and type 2 diabetes later in life. The unexpected finding that nutrition knowledge didn’t correlate with junk food consumption suggests that education alone may not be sufficient, teens may need practical support, changes to their food environment, and family involvement to make healthier choices.
This study aligns with previous research showing that ultra-processed foods are increasingly dominant in teen diets worldwide. Earlier studies have documented similar patterns in developed countries, where ultra-processed foods can account for 25-60% of daily calories depending on the population. The finding that nutrition knowledge alone doesn’t prevent junk food consumption matches other research suggesting that awareness doesn’t automatically change behavior, environmental factors, taste preferences, convenience, and peer influence play equally important roles. However, this is one of the first studies to examine these relationships specifically in an Eastern Turkish adolescent population.
This study has several important limitations. First, it’s cross-sectional, meaning it captures one moment in time and cannot prove that junk food causes health problems, only that they occur together. Second, the study relied on teenagers’ memory of what they ate, which is often inaccurate. Third, the research was conducted in one region of Turkey with a specific population, so results may not apply to all teenagers globally. Fourth, the study didn’t measure important factors like family income, food availability, or how much time teens spend on screens, which could influence both junk food consumption and body weight. Finally, the unexpected finding that diet quality scores didn’t correlate with junk food consumption suggests that the measurement tools used may not be sensitive enough to detect the specific harms of ultra-processed foods.
The Bottom Line
Moderate your consumption of ultra-processed foods to less than 20% of your daily calories (the study group averaged 27%). Focus on eating whole foods like fruits, vegetables, whole grains, and lean proteins. If you do eat packaged foods, read labels and choose options lower in added sugars, saturated fat, and sodium. Talk with family members about making healthier food choices together, since nutrition knowledge alone may not be enough. Consider practical strategies like keeping healthy snacks visible and accessible at home. These recommendations are supported by strong evidence from this and many other studies.
These findings are important for teenagers, parents, school nutrition programs, and policymakers. If you’re a teen, this research shows that even if your overall diet seems balanced, eating lots of junk food is still adding too much sugar and unhealthy fat. If you’re a parent, this suggests that teaching nutrition facts alone won’t solve the problem, you need to create an environment where healthy foods are convenient and appealing. School cafeterias and food companies should consider these findings when deciding what foods to offer. People with specific health conditions like diabetes or heart disease should be especially mindful of ultra-processed food intake.
Changes in eating habits typically take 2-4 weeks to feel normal, but health benefits develop gradually. Reduced bloating and improved energy may appear within 1-2 weeks. Improvements in body weight, blood sugar control, and cholesterol levels usually take 4-12 weeks to become measurable. Long-term benefits to heart health and disease prevention develop over months and years.
Frequently Asked Questions
How much ultra-processed food do teenagers actually eat?
According to a 2026 study of 338 teens, ultra-processed foods make up about 27% of their daily calories. The highest consumers ate more than 35% of their calories from junk food, while the lowest consumers ate less than 18.5%.
Does eating junk food affect a teenager’s weight?
A 2026 study of 338 adolescents found that ultra-processed food consumption affected body weight measurements in boys more noticeably than in girls. However, overall body mass index didn’t differ significantly across consumption levels in the full group.
Can teaching teens about nutrition help them eat less junk food?
The 2026 study of 338 adolescents found no significant connection between nutrition knowledge and junk food consumption, suggesting that education alone may not be enough. Teens need practical support, accessible healthy foods, and family involvement to make better choices.
What nutrients are teens getting too much of from ultra-processed foods?
Teens eating the most ultra-processed foods consumed significantly more added sugars, total fat, and saturated fat compared to those eating the least, according to the 2026 study. These excess nutrients are linked to obesity and heart disease.
Why don’t diet quality scores show the problems with junk food?
The 2026 study found no significant association between ultra-processed food consumption and overall diet quality scores, suggesting that standard measurement tools may not fully capture the specific harms of processed foods. More sensitive evaluation methods may be needed.
Want to Apply This Research?
- Track the percentage of your daily calories from ultra-processed foods for one week. Use the app to log everything you eat and identify which meals and snacks contain the most processed items. Aim to reduce this percentage from 27% (the study average) to below 20% over the next month.
- Set a specific goal like ‘Replace one ultra-processed snack with a whole food snack each day’ or ‘Eat one home-cooked meal instead of fast food per week.’ Use the app to plan these swaps in advance and track when you complete them. Share your goal with a friend or family member for accountability.
- Weekly check-ins: Review your ultra-processed food percentage each Sunday. Monthly progress: Track changes in energy levels, digestion, and how you feel. Quarterly assessment: Measure body weight and take photos to monitor physical changes. Use the app’s trend feature to visualize your improvement over time.
This research describes associations between ultra-processed food consumption and dietary patterns in adolescents but does not prove cause-and-effect relationships. The study was conducted in Eastern Turkey and may not apply equally to all populations. Individual responses to dietary changes vary based on genetics, overall health status, medications, and other factors. Teenagers with specific health conditions, eating disorders, or dietary restrictions should consult with a healthcare provider or registered dietitian before making significant dietary changes. This article is for educational purposes and should not replace professional medical or nutritional advice.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.
