"Can I lose weight with BJJ?" is one of the most honest questions you can ask before your first class. Often there is a second question behind it: "Shouldn't I get fitter or lose a few kilos before I start?" The answer to that one is simple: no.
The first one is harder. A small study suggests that beginners build endurance within a few weeks. Whether you also lose weight depends on more than training. Here is what the studies show, what they don't, and why we won't give you a calorie number.
How demanding is BJJ?
Very, when it counts. A review analysed how BJJ matches unfold and what they do to the body (Andreato et al., 2016):
- Long efforts, short breaks. Work phases of roughly one and a half to almost five minutes alternate with pauses of 5 to 44 seconds.
- Lots of lactate. After a match, blood lactate is clearly raised. The authors read this as a sign of moderate to high strain.
These figures come from matches. A normal class is not a competition: technique, repetitions and breaks are part of it. But training is demanding too. In the beginner study described below, heart rate during the sparring rounds averaged about 160 beats per minute for the men and 150 for the women (Lorenço-Lima et al., 2020). The authors classify that as vigorous intensity.
How many calories does a BJJ class burn?
We deliberately don't give you a number. In our review of the research, we found no reliable measurement of energy expenditure in a normal BJJ class. There are lab measurements of single exercise rounds, but a class with technique, breaks and sparring is something else. The calorie figures circulating online are estimates, not measurements.
Expenditure also varies a lot: with your body weight, with the share of technique work and free sparring, and with your partner. A single number would suggest a precision that doesn't exist.
What changes in the first weeks?
The closest match to a beginner's situation is a small study from Brazil (Lorenço-Lima et al., 2020). Sixteen sports students with no grappling experience, eight men and eight women in their early twenties, trained BJJ without the gi for six weeks, twice a week for an hour. About half of each session was sparring. Before and after, the researchers measured:
- Endurance rose, in the men and in the women. Maximal oxygen uptake, a standard measure of endurance, rose from about 46 to 51 in the men and from about 38 to 44 in the women, in millilitres per kilogram per minute.
- Leg strength rose. In the squat, the men lifted 19% and the women 29% more weight. The bench press did not change.
- Body weight and body fat did not change measurably, in either the men or the women.
Two limitations matter. The study had no control group, so part of the improvement may simply come from participants knowing the tests the second time round. And these were young sports students, not people starting after years without exercise. Eight women and eight men are too few to draw rules for everyone.
A randomised trial with 44 male competitive BJJ athletes shows what may matter if the goal is a change in the body (Wąsacz et al., 2025). For eight weeks, half trained to their usual plan and the other half followed a programme of training stations, a kind of circuit training. In the circuit group, body fat went down measurably. It was measured with skinfolds and circumferences, not with more precise methods, and the participants were experienced competitors, not beginners.
Taken together, the two studies suggest this: endurance comes with training. If you want your body to change, what seems to matter is how the training is built and what you do alongside it, not just the fact that you do BJJ.
Does BJJ make you leaner over time?
That is often claimed, but it isn't proven. There are only snapshots; no study has followed people over years of training.
- No link with years of training. Among 90 male competitive athletes with at least three years of BJJ, body fat percentage did not differ by how long they had been training (Cerqueira et al., 2022). Those competing at national or international level did have less body fat than those at state level. Whether that comes from training or from who makes it to the top in competition is something a study like this cannot show.
- A small counter-finding. In a pilot study of just 13 experienced male BJJ athletes, those with a higher belt and more BJJ experience had less body fat (Almeda et al., 2023). In the same study, strength was linked mainly to experience in strength training.
With so few and such small studies, nobody can say that BJJ makes you leaner over the years. How well other claims about BJJ hold up is collected in What BJJ really does.
Why doesn't training automatically make you lose weight?
This isn't a BJJ problem. A review of exercise and weight concludes that aerobic training at the recommended volume, on its own, usually leads to only modest weight loss, with large differences between individuals (Swift et al., 2014). The same review also stresses that exercise has many health benefits even when your weight doesn't change.
So whether you lose weight is largely decided off the mat, above all by what you eat. If you want support with that, a qualified nutrition professional is the right person to ask, not your BJJ coach.
What this means for you
- Don't measure your progress on the scale alone. If after a few weeks you last a round longer, or a technique works that didn't work last week, that is real progress, even if your weight stays the same.
- Train regularly. The World Health Organization recommends that adults get 150 to 300 minutes of moderate or 75 to 150 minutes of vigorous aerobic activity a week, plus muscle-strengthening for all major muscle groups on at least two days (Bull et al., 2020). Two to three BJJ sessions a week cover a good part of that.
- Add strength training if you want to build strength specifically.
- Choose training you'll stick with. What counts is not one hard week in January but training you are still doing a year from now. BJJ can be that kind of training: there is always a next technique to learn.
Fitness is the result, not the requirement
Many people put off starting until they are fitter or weigh less. You don't have to. We built Imperial Ground as a place where everyone feels safe and welcome, whatever your fitness and whatever your build. Here, fitness is the result of training, not the requirement.
- Built for your first day. Our Foundation classes are built for your first day. In your trial class we pair you with a training partner your size.
- Listen to your body. Our code of conduct says: "If anything feels wrong in your body, stop. Tell the coach. Sit out if needed."
- Control before intensity. In drills and sparring, your partner matches weight and resistance to you, not at full force. With big weight gaps, nobody dumps their full weight on a much smaller partner. In Foundation classes you roll under a coach's eye. We look out for each other.
- Respect, whatever your build. Everyone here is treated with dignity, "regardless of rank, size, gender, background, or experience", as the first principle of our code of conduct puts it. Respect doesn't end at the edge of the mat.
- Progress you can feel. A structured curriculum, so you feel yourself getting better class by class: after every class you know what you learned and why. That has nothing to do with the scale.
You can start in either Foundation class. Foundation No-Gi runs on Tuesdays and Thursdays at 19:00, 90 minutes each, without a gi, in sports clothes. Foundation Gi runs on Mondays and Wednesdays at 19:00 (90 minutes) and Fridays at 18:00 (60 minutes). What your first evening looks like is covered in Starting BJJ in Düsseldorf.
To be honest: what the studies don't show
- The studies are small and short. The two training studies had 16 and 44 participants, over six and eight weeks. The two comparison studies, with 90 and 13 athletes, are snapshots and show only associations.
- Women have barely been studied. Almost all participants in these studies were men. Women took part only in the beginner study, eight of them.
- A control group is often missing. In the beginner study, that means nobody can say cleanly what is down to the training.
- We found no reliable measurement of energy expenditure in a normal BJJ class.
- Body fat is measured in different ways, sometimes with bioimpedance, sometimes with skinfolds. Values from different methods can't be compared directly.
- That BJJ makes you leaner over time is not proven. No study has followed people over years of training.
Frequently asked questions
Can you lose weight with BJJ?
Nobody can promise that. In a small study of 16 beginners, endurance rose after six weeks, but body fat did not change measurably. Whether you lose weight is largely decided off the mat, above all by what you eat.
Do I need to be fit to start BJJ?
No. Fitness is the result of training, not the entry ticket. Our Foundation classes are built for your first day, and if anything feels wrong in your body, you stop and tell the coach.
How many calories does a BJJ class burn?
We found no reliable measurement. Calorie figures online are estimates, and expenditure varies a lot with body weight, pace and what the class covers.
Is BJJ a good full-body workout?
It demands endurance and strength at the same time. In a small study, beginners improved their endurance and leg strength after six weeks, but not their bench press.
Gi or No-Gi: which is more demanding?
No study has compared them directly. The beginner study was done without the gi. You can start in either Foundation class with us.
How often should I train?
Two to three sessions a week is a good start. The WHO recommends that adults get 150 to 300 minutes of moderate or 75 to 150 minutes of vigorous activity a week, plus muscle-strengthening on at least two days.
Do I need strength training as well?
The WHO recommends muscle-strengthening on at least two days a week. In a small BJJ study, strength was linked mainly to experience in strength training.
Sources
- Andreato LV, Follmer B, Celidonio CL, Honorato AS. Brazilian Jiu-Jitsu Combat Among Different Categories: Time-Motion and Physiology. A Systematic Review. Strength & Conditioning Journal 2016;38(6):44–54. https://doi.org/10.1519/SSC.0000000000000256
- Lorenço-Lima L, Souza-Junior TP, Okuyama AR, McAnulty SR, Utter AC, Monteiro TS, Barquilha G, Bortolon JR, Geraldo TP, Hirabara SM. Characterization of Brazilian Jiu-Jitsu training effects on the physical fitness of men and women. Journal of Physical Education and Sport 2020;20(Suppl 5), Art. 406:2990–2995. https://doi.org/10.7752/jpes.2020.s5406
- Wąsacz W, Rydzik Ł, Kryst Ł, Spieszny M, Jaworski J, Ambroży T. The Impact of the Experimental 'Grappler Quest' Training on the Structural Profile of Brazilian Jiu-Jitsu Athletes: A Randomized Controlled Trial. Applied Sciences 2025;15(18):10048. https://doi.org/10.3390/app151810048
- Cerqueira BS, Cerqueira MB, Ferreira WC, de Oliveira FM, Andreato LV, dos Santos-Junior RB, Valdés-Badilla P, Branco BHM. Proposal of a Normative Table for Classification of Body Fat Percentage in Brazilian Jiu-Jitsu Athletes. International Journal of Morphology 2022;40(1):57–61. https://doi.org/10.4067/S0717-95022022000100057
- Almeda CG, Mangine GT, Green ZH, Feito Y, French DN. Experience, Training Preferences, and Fighting Style Are Differentially Related to Measures of Body Composition, Strength, and Power in Male Brazilian Jiu Jitsu Athletes: A Pilot Study. Sports 2023;11(1):13. https://doi.org/10.3390/sports11010013
- Swift DL, Johannsen NM, Lavie CJ, Earnest CP, Church TS. The role of exercise and physical activity in weight loss and maintenance. Progress in Cardiovascular Diseases 2014;56(4):441–447. https://doi.org/10.1016/j.pcad.2013.09.012
- Bull FC, Al-Ansari SS, Biddle S, et al. World Health Organization 2020 guidelines on physical activity and sedentary behaviour. British Journal of Sports Medicine 2020;54(24):1451–1462. https://doi.org/10.1136/bjsports-2020-102955
About the author. João Macedo is a 1st-degree black belt in Brazilian Jiu-Jitsu, has been on the mats for more than 14 years, and is co-founder and head coach of Imperial Ground Martial Arts in Düsseldorf-Derendorf.
Read on: What BJJ really does · Why BJJ can be training you keep for years · Pillar 4 · Movement · Is BJJ dangerous?