A 2026 study of 25 professional handball players found that eating a Paleo diet for 8 weeks did not change resting metabolic rate compared to a regular balanced diet, even though the diets were very different in food types. According to Gram Research analysis, when total calories were held equal, both groups burned calories at the same rate while resting, suggesting that diet type alone doesn’t boost metabolism.
According to Gram Research analysis, a new study tested whether the Paleo diet could speed up how fast athletes burn calories at rest. Researchers compared 25 professional handball players—some eating Paleo and others eating a regular balanced diet—for 8 weeks. Both groups ate the same total calories. The results showed no difference in resting metabolic rate between the two diets. This suggests that while the Paleo diet may have other benefits, it doesn’t give athletes a metabolic advantage just by changing what they eat.
Key Statistics
A 2026 randomized controlled trial published in Scientific Reports involving 25 professional handball players found no significant differences in resting metabolic rate between those following a Paleo diet and those eating a regular balanced diet over 8 weeks.
Research from 2026 showed that when 14 handball players ate a Paleo diet and 11 ate a regular diet with equal total calories for 8 weeks, both groups showed identical resting metabolic rates, oxygen consumption, and substrate utilization patterns.
A 2026 study measuring metabolism with indirect calorimetry in 25 athletes found zero difference in how much energy the body burned at rest between Paleo and regular diet groups, despite the diets having different food compositions.
The Quick Take
- What they studied: Whether eating a Paleo diet (meat, vegetables, nuts, no grains or dairy) changes how many calories your body burns while resting, compared to a regular balanced diet
- Who participated: 25 professional handball players split into two groups: 14 eating Paleo and 11 eating a regular diet for 8 weeks. Both groups ate the same total number of calories.
- Key finding: After 8 weeks, there was no difference in resting metabolic rate between the Paleo diet group and the regular diet group. Both groups burned calories at the same rate while resting.
- What it means for you: If you’re thinking about switching to a Paleo diet hoping it will speed up your metabolism, this research suggests that won’t happen—at least not in the short term. However, this doesn’t mean the Paleo diet has no benefits; it just doesn’t appear to boost how fast you burn calories at rest.
The Research Details
This was a controlled experiment where researchers carefully divided handball players into two groups. One group followed a Paleo diet (focusing on meat, fish, vegetables, nuts, and fruits while avoiding grains, dairy, and processed foods) while the other group ate a regular balanced diet. The key detail: both groups ate the exact same number of total calories—this is called a “normoenergetic” diet, meaning the energy in equals the energy out on paper.
For 8 weeks, researchers measured how fast each player’s body burned calories while resting using a special machine called an ergospirometer. This machine measures the oxygen you breathe in and carbon dioxide you breathe out, which tells scientists exactly how many calories your body is using. The researchers also measured what type of fuel your body was using (carbohydrates, fat, or protein).
This approach is strong because it controls for total calories—a common problem in diet studies where people accidentally eat more or less. By keeping calories equal, researchers could see if the type of food mattered, not just the amount.
Many people believe certain diets can “speed up” metabolism, but metabolism is complicated. This study matters because it tests that belief in real athletes using precise scientific equipment. If the Paleo diet truly boosted metabolism, we’d expect to see it in athletes—a group that’s already fit and whose bodies are sensitive to changes. The fact that it didn’t show an effect here suggests the Paleo diet’s benefits (if any) come from other factors, not from burning more calories at rest.
This study has several strengths: it used precise scientific equipment to measure metabolism, it controlled for total calories eaten, and it lasted 8 weeks (long enough to see changes). However, the sample size was small (only 25 people), and all participants were professional athletes, so results may not apply to regular people. The study was published in Scientific Reports, a respected journal. One limitation is that 8 weeks might not be long enough to see all possible effects, and we don’t know if results would differ in non-athletes.
What the Results Show
The main finding was straightforward: the Paleo diet group and the regular diet group showed no differences in resting metabolic rate after 8 weeks. Both groups burned approximately the same number of calories while at rest. The researchers measured multiple aspects of metabolism—oxygen intake, carbon dioxide output, and how much carbohydrate, fat, and protein each body was using—and found no meaningful differences between groups.
This was somewhat surprising because the Paleo diet is quite different from a regular diet in terms of food types. You might expect such a different eating pattern to change how the body works. However, when total calories are held constant, the type of food doesn’t appear to matter for resting metabolism in this population.
The study also looked at how much energy came from burning each type of fuel (carbs, fat, and protein), and again found no differences. This suggests that even though Paleo and regular diets have different ratios of these nutrients, the body adapts and uses them similarly when total calories are the same.
The researchers measured the respiratory quotient (RQ), which is a ratio that shows what type of fuel your body is preferring to burn. Interestingly, this also showed no significant difference between groups. In theory, a Paleo diet (which is lower in carbs) might shift the body toward burning more fat, but this didn’t happen in a measurable way over 8 weeks. The study also found no differences in how much oxygen the athletes’ bodies used or how much carbon dioxide they produced.
Previous research has shown that the Paleo diet may help with weight loss and body composition (how much muscle versus fat you have), but those studies often didn’t control for total calories. This study is important because it separates the question: does Paleo help because you eat fewer calories, or because of something special about the diet itself? The answer appears to be that when calories are equal, the diet type doesn’t change resting metabolism. This aligns with broader nutrition science showing that total calories matter more than diet type for basic metabolic rate.
This study has several important limitations. First, only 25 people participated, which is a small group—results might be different with more participants. Second, all participants were professional handball players, so we don’t know if these results apply to regular people, older adults, or people with different fitness levels. Third, the study only lasted 8 weeks; longer studies might show different results. Fourth, the study measured resting metabolism but didn’t measure total daily energy expenditure (how many calories people burned during exercise and daily activities). Finally, we don’t know if the Paleo diet might have other benefits not measured here, like improvements in energy levels, digestion, or athletic performance.
The Bottom Line
Based on this research, don’t switch to a Paleo diet expecting it to speed up your metabolism or help you burn more calories at rest. If you’re interested in the Paleo diet for other reasons (like how you feel, digestion, or food preferences), that’s a personal choice, but metabolism boost isn’t a supported benefit based on this evidence. If weight loss is your goal, focus on total calories eaten rather than which specific diet you choose. (Confidence level: Moderate—this is one study in athletes, so results may vary.)
This research is most relevant to athletes and active people considering the Paleo diet for performance or metabolic reasons. It’s also useful for anyone who’s heard claims that Paleo “speeds up metabolism.” However, people interested in Paleo for other reasons (food sensitivities, personal preference, or other health goals) can make their own choice. This study doesn’t say Paleo is bad—just that it doesn’t boost resting metabolism.
If you were to try a Paleo diet, you wouldn’t expect to see changes in resting metabolic rate within 8 weeks based on this research. Any weight loss benefits would likely come from eating fewer total calories, not from metabolism changes, and those could take weeks to months to become noticeable.
Frequently Asked Questions
Does the Paleo diet speed up your metabolism?
A 2026 study of 25 athletes found no difference in resting metabolic rate between Paleo and regular diets when total calories were equal. The Paleo diet does not appear to boost how fast your body burns calories at rest.
Can eating Paleo help you lose weight faster?
This study suggests weight loss from Paleo would come from eating fewer total calories, not from metabolism changes. Any diet works for weight loss if it helps you eat less overall—the specific foods matter less than the total amount.
Is the Paleo diet better for athletes than regular diets?
This research shows Paleo doesn’t change resting metabolism in athletes. While athletes might feel better on certain diets for personal reasons, this study found no metabolic advantage to Paleo when calories are controlled.
How long does it take for diet changes to affect metabolism?
This 8-week study found no metabolic changes from switching to Paleo. Resting metabolism appears stable regardless of diet type when calories stay the same, though longer-term effects remain unclear.
What actually determines how fast your metabolism is?
Resting metabolism is primarily determined by body size, muscle mass, age, and genetics—not by which diet you eat. This study shows that diet type doesn’t significantly change your baseline metabolic rate.
Want to Apply This Research?
- Track your resting heart rate daily (measured first thing in the morning before getting out of bed) and your total daily calories. While this study shows diet type doesn’t change resting metabolism, monitoring these metrics helps you see if your overall energy expenditure changes over time.
- If trying a Paleo diet, use the app to log all foods and track total calories rather than focusing on which foods are “allowed.” This helps you see that metabolism changes come from calorie balance, not diet type. Set a realistic calorie goal based on your activity level.
- Over 8-12 weeks, track weekly average resting heart rate and compare it to your calorie intake. If you’re not seeing the results you want, adjust total calories rather than switching between diet types. Use the app to identify which specific foods help you feel full and energetic.
This research applies specifically to professional handball players and may not reflect results in other populations. This study measured resting metabolic rate only and does not address other potential benefits or drawbacks of the Paleo diet. Before making significant dietary changes, especially if you have health conditions, take medications, or have specific fitness goals, consult with a healthcare provider or registered dietitian. This article is for informational 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.