According to Gram Research analysis, teenagers who eat more plant-based proteins like beans, lentils, nuts, and whole grains show significantly better heart and lung fitness compared to those eating less plant protein. A 2026 study of 1,677 adolescents found that plant protein intake was positively associated with cardiorespiratory fitness in both boys and girls, while animal protein showed no similar connection. This suggests that shifting toward more plant-based protein sources may help teens maintain stronger cardiovascular fitness as they age.
A new study of nearly 1,700 teenagers found that eating more plant-based proteins—like beans, nuts, and whole grains—is linked to better heart and lung fitness. Researchers from the HELENA study measured different types of fitness in boys and girls ages 12 to 17, then looked at what they ate over three days. The surprising finding: plant protein showed a clear connection to cardiorespiratory fitness, while animal protein didn’t show the same benefit. This research supports encouraging teens to eat more plant-based foods to keep their fitness levels strong as they grow older.
Key Statistics
A 2026 study of 1,677 adolescents (796 boys and 881 girls) ages 12-17 found that plant-based protein intake was significantly associated with better cardiorespiratory fitness in both sexes, while animal protein showed no meaningful connection to any fitness measure.
According to Gram Research analysis of the HELENA study, the association between total protein intake and heart-lung fitness was significant in boys but not girls, suggesting sex differences in how protein sources influence cardiovascular fitness development during adolescence.
The 2026 research found no significant associations between any protein source and muscular strength, flexibility, or explosive leg power, indicating that plant protein’s fitness benefits appear specific to cardiovascular function rather than affecting all fitness components equally.
The Quick Take
- What they studied: Whether different types of protein (plant-based vs. animal-based) affect how fit teenagers are, including their heart and lung strength, muscle power, and flexibility.
- Who participated: 1,677 teenagers (796 boys and 881 girls) between ages 12 and 17 from the HELENA study, a large European research project tracking teen health.
- Key finding: Teens who ate more plant-based proteins had noticeably better heart and lung fitness. Animal protein didn’t show this same connection. For boys specifically, total protein intake also mattered for heart fitness.
- What it means for you: Eating more plant-based proteins like beans, lentils, nuts, and whole grains may help teenagers build better cardiovascular fitness. This doesn’t mean cutting out all animal protein, but adding more plant options could be beneficial. Results are strongest for heart and lung fitness rather than muscle strength or flexibility.
The Research Details
Researchers tested 1,677 teenagers on four different fitness measures: how strong their upper body was, how well their heart and lungs worked during exercise, how flexible they were, and how powerfully their legs could jump. They asked each teen to recall everything they ate over three separate days to measure their protein intake. Then they used statistical tools to see if the type of protein they ate connected to their fitness results, while accounting for other factors like age and overall activity level.
The study looked at two main protein sources: plant-based (from foods like beans, nuts, seeds, and grains) and animal-based (from meat, fish, eggs, and dairy). This approach let researchers compare whether the source of protein mattered, not just the total amount eaten.
Understanding which foods help teens stay fit is important because fitness levels naturally decline as people age. If plant-based proteins can help prevent this decline, it’s valuable information for teens, parents, and doctors. This research also connects nutrition to fitness in a real-world setting with actual teenagers, making the findings more relevant than lab studies alone.
This study used standardized fitness testing procedures, meaning all teens were tested the same way. The sample size was large (1,677 participants) and included both boys and girls, making results more reliable. However, the study measured diet over just three days, which may not represent what teens eat all the time. The research shows association (connection) but not necessarily cause-and-effect, so we can’t say plant protein definitely causes better fitness.
What the Results Show
The most important finding was that plant-based protein intake showed a clear positive connection to cardiorespiratory fitness—the ability of the heart and lungs to work efficiently during exercise—in both boys and girls. This connection remained strong even after researchers adjusted for other factors that might affect fitness, like age, body weight, and physical activity levels.
Interestingly, animal protein intake (from meat, fish, eggs, and dairy) did not show this same connection to any fitness measure in either boys or girls. This suggests that the source of protein matters, not just the total amount. For boys only, total protein intake was linked to better heart and lung fitness, but this pattern didn’t appear in girls.
No significant connections were found between any protein source and the other fitness measures tested: upper body strength, flexibility, or lower body explosive power (jumping ability). This means plant protein’s benefit appears specific to cardiovascular fitness rather than affecting all types of fitness equally.
The study found no meaningful associations between protein intake and muscular strength, flexibility, or explosive leg power in either boys or girls. This suggests that while protein is important for building muscle, the type of protein source may not be the key factor for these particular fitness components. The differences between boys and girls in how total protein affected fitness suggest that sex may play a role in how protein influences fitness development during adolescence.
Previous research has shown that plant-based diets are generally associated with better cardiovascular health in adults. This study extends that finding to teenagers, suggesting the benefits may start earlier than previously thought. The finding that plant protein specifically benefits heart and lung fitness aligns with research showing that plant foods contain beneficial compounds like fiber and antioxidants that support cardiovascular function. However, most previous studies haven’t directly compared plant versus animal protein sources in teen fitness, making this research a valuable addition to the field.
The study measured diet using three-day dietary recalls, which may not accurately represent what teens typically eat throughout the year. Seasonal eating patterns, special occasions, and individual variation could affect results. The research shows association but cannot prove that plant protein causes better fitness—other factors like overall diet quality or lifestyle habits could explain the connection. The study is also observational, meaning researchers watched what happened rather than randomly assigning teens to eat different diets. Results may not apply equally to all ethnic groups or countries since participants were from Europe.
The Bottom Line
Teenagers should aim to include more plant-based protein sources in their diet, such as beans, lentils, chickpeas, nuts, seeds, tofu, and whole grains. This doesn’t require eliminating animal proteins but rather adding more plant options. The evidence is moderately strong for cardiovascular fitness benefits. Parents and teens should view this as part of a broader healthy eating pattern that includes plenty of fruits, vegetables, and whole grains alongside regular physical activity.
This research is most relevant for teenagers, parents, school nutrition programs, and coaches looking to support teen fitness development. It’s particularly useful for teens interested in improving their cardiovascular fitness and endurance. The findings may be less directly applicable to very young children or adults, though the principles likely extend across age groups. Teens with specific fitness goals, such as distance runners or soccer players, may find this information especially valuable.
Changes in cardiovascular fitness from dietary changes typically take several weeks to months to become noticeable. Teens who consistently increase plant-based protein intake might expect to see improvements in endurance and heart-lung fitness within 4-8 weeks of regular physical activity combined with dietary changes. Long-term benefits develop over months and years as fitness adaptations accumulate.
Frequently Asked Questions
Does eating more plant-based protein help teenagers get more fit?
Research shows plant-based protein is linked to better heart and lung fitness in teens. A 2026 study of 1,677 adolescents found this connection in both boys and girls, though benefits appear specific to cardiovascular fitness rather than muscle strength or flexibility.
What plant-based proteins should teenagers eat for better fitness?
Good plant-based protein sources include beans, lentils, chickpeas, nuts, seeds, tofu, tempeh, and whole grains. These foods provide protein plus beneficial fiber and antioxidants that support heart and lung health during exercise.
Is animal protein bad for teen fitness?
Animal protein isn’t bad—the study found it simply wasn’t associated with better fitness. Teens can eat both plant and animal proteins. The key finding is that adding more plant-based options may provide additional cardiovascular benefits.
How long does it take to see fitness improvements from eating more plant protein?
Cardiovascular fitness improvements typically appear within 4-8 weeks of consistent dietary changes combined with regular physical activity. Long-term benefits develop over months and years as fitness adaptations accumulate in the body.
Does this study apply to all teenagers or just certain groups?
The study included 1,677 European teenagers ages 12-17 of both sexes. Results may vary by ethnicity, geography, and individual factors. Consult healthcare providers about applying findings to specific teen populations or health conditions.
Want to Apply This Research?
- Track daily plant-based protein sources consumed (beans, lentils, nuts, seeds, tofu, whole grains) and log weekly cardiovascular fitness activities (running, cycling, swimming). Measure progress by noting improvements in endurance, such as running distance or duration without stopping.
- Set a goal to include one plant-based protein source at two meals per day. Users can log meals and receive suggestions for plant-based protein swaps (like chickpea pasta instead of regular pasta, or bean chili instead of meat chili). Track which plant proteins they enjoy most to build sustainable habits.
- Create a weekly dashboard showing plant-based protein intake trends and correlate it with cardiorespiratory fitness metrics like resting heart rate, running pace, or endurance test results. Set monthly fitness goals and review whether increased plant protein intake correlates with improvements.
This research shows an association between plant-based protein intake and cardiovascular fitness in teenagers but does not prove cause-and-effect. Individual results vary based on genetics, overall diet quality, physical activity levels, and other health factors. Teenagers should consult with their healthcare provider or registered dietitian before making significant dietary changes, especially if they have existing health conditions, food allergies, or nutritional concerns. 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.
