It’s a familiar worry among clients and trainers, that working out makes you ravenous. The assumption is that the harder you train, the more you’ll want to eat. Before long any calorie deficit will be wiped out by an uncontrollable craving for crisps, pasta or that mysterious third helping of dinner. But what if that’s not quite how it works?
A new study published in Frontiers in Public Health challenges this idea, showing that resistance training (RT) at the right intensity might actually help curb overeating. Not only that, but different training intensities seem to influence how much and what people eat. For PTs, S&C coaches, and nutrition coaches, it’s a fascinating window into how training style shapes client behaviour without relying on restrictive food plans or crash diets.
And if you’re on the hunt for PT courses or personal training courses that actually help you guide clients through this kind of behavioural change, this kind of research is exactly why a solid foundation in both exercise and nutrition is so important.
Let’s dig into what the study found and how you can use it with your clients.
The Study That Measured Both Training & Eating
Researchers Wang et al. (2025) designed a 12-week randomised controlled trial to see how different intensities of resistance training affected overweight and obese college women. They looked at both body composition and how much they ate.
Participants were split into four groups including high-intensity (HI), moderate-intensity (MI), low-intensity (LI), and a control group that followed a standard PE class. Each RT group trained three times a week for an hour. Exercises included squats, presses, pulldowns and curls, with volume matched across all groups. This meant any differences in results could be attributed to intensity and not total workload.
They also tracked food intake using 3-day diet diaries, looking at total calories, protein, fat, carbohydrates and meal timing. That’s what makes this study so useful as it links training directly to how people actually behaved around food.
High Intensity Lead to Less Food, Fewer Carbs
Let’s start with the heavy lifters. The high-intensity group (training at 75–80% of 1RM) saw the biggest drops in both body fat and carbohydrate intake. On average, participants consumed around 462 fewer calories per day, and carb intake dropped significantly more than in the control group or the low-intensity group.
What’s more interesting is that these reductions weren’t necessarily due to conscious dieting. The study found positive correlations between changes in body fat percentage and reductions in protein and carb intake. In other words, those who improved their body comp the most also seemed to naturally eat differently when lifting heavy.
This supports other studies that suggest intense resistance exercise blunts appetite in the short term and changes hormonal signals over time. For instance, ghrelin (a hunger hormone) often drops post-exercise, while satiety hormones like peptide YY and GLP-1 increase. This is most common after high-intensity work. A meta-analysis by Hu et al. (2023) backs this up, showing high-intensity exercise is more likely to reduce appetite than moderate aerobic activity.
For us as personal trainers, this is a huge takeaway. Clients who lift heavy may end up regulating their own intake without even being told to “eat clean” or “track macros.”
The Sweet Spot for Macronutrient Shifts
If high intensity reduced carbs and overall energy, moderate intensity (training at 60–65% of 1RM) hit another sweet spot. Moderate intensity training caused the biggest drop in protein and fat intake and the largest overall calorie reduction, clocking in at almost 600 fewer kcal per day.
Moderate intensity seems to offer a balanced training stimulus that affects appetite-regulating hormones without triggering rebound hunger. While high-intensity training can sometimes provoke compensatory eating in the very hungry or very untrained, moderate loads appear to exert enough physical demand to change metabolism and mood without pushing people over the edge.
There’s even emerging evidence that this intensity bracket is ideal for improving insulin sensitivity, appetite control and energy balance in the general population. A study by Echeverria et al. (2020) found that moderate RT improved nutritional status and reduced intake in older adults, and Rahmani Ghobadi et al. (2016) saw similar effects in overweight women. It might just be that moderate-intensity training is better tolerated and more sustainable for many, beginners in particular.
This could explain why the MI group showed across-the-board improvements in body composition, food intake and appetite cues. When working with lifestyle clients, that is those juggling jobs, kids and stress, moderate might not just be “good enough.” It might be ideal.
Minimal Change From Low Intensity
And what about the low-intensity group (training at 45–50% 1RM) and the standard PE class control group?
They showed the least change in both in body composition and in diet. While there were small improvements in body fat and waist circumference, changes in protein, fat and carbohydrate intake were negligible. The control group even showed negative correlations between body changes and intake which suggests that as some women lost a bit of weight, they may have increased their intake or adjusted it in ways that weren’t productive.
This reinforces what many of us see in practice. General PE-style workouts aren’t structured enough to create meaningful adaptation. And light resistance training, while better than nothing, doesn’t trigger the hormonal or psychological shifts that change how people approach food.
Appetite & Overeating
The standout from the study is how resistance training intensity influenced appetite and eating behaviour as well as body composition. High and moderate groups showed consistent reductions in energy intake, and the more their bodies changed, the more their intake improved. Meanwhile, in the control group, food intake and body composition often moved in opposite directions.
This is a big shift from the old assumption that exercise automatically makes people hungrier. It turns out the type and intensity of exercise matter a lot. While long aerobic sessions can drive up appetite (especially in lean individuals), resistance training seems to do the opposite. Even more so when intensity is dialled in just right.
What to do with this Information.
First, if you’re helping clients manage weight or improve health through training, resistance training needs to be on the menu. It needs to more than just a token effort. High or moderate intensity works best.
Second, you don’t need to start with strict food rules. Many clients will naturally reduce intake of their carbs and fats when their training is properly structured. That’s especially important for clients who’ve had negative experiences with dieting or restrictive food plans.
Third, observe and personalise. Some clients may respond better to high-intensity work, while others thrive with moderate. You can experiment with block programming, track intake patterns and guide clients toward what feels sustainable. Remember we’re not just looking for what burns the most calories on paper.
Final Thoughts
We often think of training and nutrition as separate pillars. That is one which builds muscle and the other that burns fat. But this study reminds us they’re deeply connected. Train harder and smarter and your clients may eat differently without even trying. Which is the kind of sustainable change most people are really looking for.
If you’re teaching clients how to move better and eat well, don’t just think about workouts or food plans. Have an understanding of how those two worlds interact and you will really see the beginnings of great transformations.
Reference
- Wang Q, Xiao WS, Danaee M, et al. (2025). Impact of resistance training intensity on body composition and nutritional intake among college women with overweight and obesity: a cluster randomized controlled trial. Front. Public Health. 13:1589036. Click here to review the full research article.
- Hu M, Nie J, Lei OK, Shi Q, Kong Z. (2023). Acute effect of high-intensity interval training versus moderate-intensity continuous training on appetite perception: a systematic review and meta-analysis. Appetite, 182:106427. Click here to review the full research article.
- Echeverria I, Amasene M, Urquiza M, Labayen I, Anaut P, Rodriguez-Larrad A, et al. (2020). Multicomponent physical exercise in older adults after hospitalization: a randomized controlled trial comparing short- vs. long-term group-based interventions. International Journal of Environmental Research and Public Health, 17(2):666. Click here to review the full research article.
- Rahmani Ghobadi M, Rahmaninia F, Mirzaei B, Hedayati M. (2016). Effects of 8 weeks of aerobic training on Agouti-related peptide, appetite hormones and insulin resistance in overweight sedentary women. Pars Journal of Medical Sciences, 14(2):1–8. Click here to review the full research article.
Help Clients Eat Less Without Dieting as a Nutrition & Exercise Specialist
If you’re serious about helping clients improve not just how they train but how they eat, the Nutrition & Exercise Specialist and Master Diplomas™ are for you. A recent study found that women doing moderate-intensity resistance training reduced their daily calorie intake by nearly 600 kcal and saw the biggest drops in protein and fat intake — without any restrictive dieting. Meanwhile, high-intensity training led to the largest reductions in body fat percentage and carbohydrate intake. These findings highlight exactly why understanding the relationship between training intensity and nutrition is essential for results that last. Our diplomas combine advanced exercise knowledge with evidence-based nutritional strategies, so you can coach your clients more effectively — and with confidence. Learn more here: Nutrition & Exercise Diplomas
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