Pilates and body composition: what posture and fat studies show

What posture and core endurance trials actually established

In the trial involving women with obesity, Pilates was reported to prevent increases in BMI and body fat percentage. That is a different finding from a substantial reduction in fat. Preventing a measurement from rising and reducing it from its starting value describe different directions of change. Among women without obesity, no effect on BMI or body fat percentage was found. Those details are essential to the conclusion, even though both populations took part in the same overall study.[14]

Posture scores improved regardless of obesity status. Among women with obesity, emotional eating and social physique anxiety scores fell, while self-esteem scores rose. Women without obesity did not show the same significant psychosocial changes. Researchers used dedicated scales before and after the program to assess eating behavior, anxiety about the body and self-esteem. The study thus followed physical and psychological outcomes in parallel, rather than treating a posture score as a summary of everything that changed.[14]

Connecting psychological changes to physical changes would require evidence about their sequence and mechanism. This trial’s women with obesity were divided into 15 Pilates participants and 15 controls; women without obesity were divided into groups of 14. These were small groups, and the results differed by obesity status. The findings should be read as outcomes in those populations, rather than as proof of a universal pathway from feeling better to losing fat. Our feature on stress and emotional eating addresses the wider eating-behavior topic.[14]

For core endurance, a separate trial involved 19 women who already had Pilates experience. They trained on Reformer and Cadillac equipment at least twice weekly for 10 weeks. Participants were randomly allocated to a protein supplement or a comparison supplement, and researchers measured body composition, torso muscle endurance and flexibility. The presence of previous Pilates experience matters when interpreting the findings: this was a trial in trained women, not a trial describing how every beginner responds.[7]

Core muscle endurance and flexibility improved after training, but supplementation did not add a benefit. Both groups performed Pilates, so the randomized comparison directly tested the effect of the supplement. There were 10 participants in the comparison supplement group and 9 in the protein group. Participants, intervention providers, investigators and outcome assessors were blinded to group assignment. That design strengthens the supplement comparison, while leaving the important distinction that neither group was a non-exercising control.[7]

Participants’ mean age was 31, and their habitual dietary protein intake averaged 1.3 g per kg of body weight daily. Dietary intake was monitored throughout the study. The protein group received an additional 0.6 g per kg daily, without outperforming the comparison supplement group. These amounts describe the dietary background and intervention in this group of experienced women.[7]

Equipment and measurement methods change what you can conclude

Equipment-based research has also compared exercise with a control group in women selected by age and body size. A randomized trial included 47 women aged 30–60 with overweight or obesity. Participants in the exercise group performed Reformer Pilates three times weekly for 8 weeks. The trial therefore addresses a particular equipment program in a particular population; its result cannot simply replace the result of the broader mat Pilates analysis.[15]

The researchers reported a significant body composition finding in the Reformer group, alongside improvements in upper-limb strength and muscular endurance and reductions in depression and anxiety. However, the reported abstract did not give changes in kilograms of fat or lean mass. There was no significant between-group difference in sleep quality. A positive result for one outcome does not supply a missing numerical change for another, and it does not make the unfavorable sleep finding disappear.[15]

The exercise group included 23 women and the control group 24. Their mean ages were approximately 46.7 and 45.4 years, respectively. Participants had a BMI of at least 25. Upper-limb strength was assessed with a handgrip dynamometer, muscular endurance with torso endurance tests, and body composition with bioelectrical impedance. Questionnaires assessed sleep quality, depression and anxiety. All outcomes were assessed before training and after 8 weeks. Participants, comparison conditions and measurements differed from the mat review, so these studies cannot directly rank equipment and mat Pilates for weight loss.[3][15]

Measurement methods deserve their own attention. In the trial of experienced women, body composition was assessed using bioelectrical impedance analysis, or BIA, and dual-energy X-ray absorptiometry, or DXA. BIA uses electrical measurements, while DXA uses X-rays. The correlation coefficients between the methods for whole-body fat and lean mass exceeded 0.78. After training, however, BIA estimated more lean mass than DXA. Strong correlation therefore did not make the measurements interchangeable.[7]

BIA showed a reduction in body fat and increases in lean mass, total body water and extracellular water, meaning water outside cells. DXA showed increases in arm lean mass, trunk bone mineral content and trunk bone area. Hip circumference also decreased. These changes were observed regardless of supplement assignment. The findings go beyond what weight alone describes, but they also show why an increase in BIA lean mass should not be restated as an increase in whole-body muscle. Water changed too, and the reported DXA lean mass increase concerned the arms.[7]

A trial in Spain examined a different population: 109 community-dwelling women aged 60 or older. Researchers randomly allocated 55 women to Pilates and 54 to a control group and evaluated a 12-week program. They measured body composition, handgrip strength and physical performance before and immediately after the intervention. Handgrip strength and physical performance improved significantly both within and between groups. There was no significant difference in the height-adjusted skeletal muscle mass index.[18]

Body composition was assessed using BIA, with BMI, body fat percentage and height-adjusted skeletal muscle mass among the outcomes. Physical performance was estimated through a timed test of standing up, walking and returning. The between-group effect size was 0.52 for handgrip strength and 0.87 for physical performance. Effect sizes express the magnitude of differences on an appropriate scale. BMI decreased significantly only within the Pilates group, with a small effect size of 0.07. The researchers concluded that strength and performance benefited, but the program failed to induce body composition changes.[18]

Common misconceptions

“Working the core means belly fat goes first.” The torso endurance trial did not establish preferential loss of abdominal fat, and the meta-analysis in adults with overweight or obesity found no significant effect on waist circumference. Feeling the abdomen work is not the same evidence as measuring a change in abdominal fat. A movement can be relevant to a core endurance goal without supplying the answer to a waist-size question.[1][7]

“If the scale does not move, Pilates has failed.” Studies reported improvements in posture, strength and physical performance. Posture improved in the 8-week trial of 58 women, and handgrip strength and physical performance improved in the 12-week trial of 109 older women. The former separated participants by obesity status; the latter involved community-dwelling women aged 60 or older. These are different populations evaluated over different periods. They support attention to specific outcomes, rather than an expectation that every benefit must arrive with weight loss.[14][18]

“With so many papers, the weight-loss effect must be settled.” An umbrella review, which reviews systematic reviews, assessed 27 reviews containing meta-analyses. Of these, 1 was rated high quality, 1 moderate quality, 15 low quality and 10 critically low quality. Those figures describe reviews across multiple health topics, including body composition. They are not a quality breakdown solely of weight-loss research. The number of reviews alone therefore does not tell you how secure a specific body composition conclusion is.[12]

The umbrella review reported benefits including BMI and body fat percentage, while rating certainty from very low to moderate and describing much of the evidence as low certainty. Its search extended to February 2023 and covered circulatory, metabolic, musculoskeletal, neurological, sleep and other health topics. Methodological quality and certainty of evidence were assessed separately. The authors called for further high-quality randomized controlled trials. Favorable findings and a need for stronger confirmation can both be true within the same research summary.[12]

What you can do today

• If posture is your goal, put Pilates twice weekly into a realistic schedule. That was the frequency in the trial of 58 women, which ran for 8 weeks and found improved posture scores. Treat the schedule as a study example, rather than a guarantee that everyone’s posture will change by that point.[14]
• If you already choose equipment-based Pilates, compare your available time with the Reformer trial’s three sessions weekly for 8 weeks. Exercise at a frequency you can reasonably attend. The participants were women aged 30–60 with overweight or obesity, so keep that context attached to the example.[15]
• Review the protein in your usual meals and use your everyday menu as the starting point for dietary decisions. In 19 experienced women, habitual dietary intake averaged 1.3 g/kg daily; adding another 0.6 g/kg daily did not improve the training results. These are the study participants’ intake amounts, not a target for everyone. Consider that dietary background when deciding whether supplements have a role.[7]
• If you measure body composition, record the device alongside the result and review the trend using the same device. For posture, have an instructor look at the movements you practice and identify what to work on at the next lesson. The equipment trial’s BIA and DXA findings illustrate why the measurement method belongs with the number.[7]

Fitting Pilates into your week at On the Shore Tachikawa

Whether your Pilates goal concerns posture or core endurance, choose lesson times you can keep attending. On the Shore Tachikawa offers a place to maintain that exercise habit.

On the Shore Tachikawa is a lava-stone hot yoga studio offering Pilates, a 1-minute walk from the North Exit of JR Tachikawa Station. It is open every day 8:00–23:30, at 3F Etoile Bldg, 2-14-10 Akebonocho, Tachikawa, Tokyo. Compare those hours with the time you can set aside each week.

Check the participation conditions while choosing which activity to put in your weekly schedule. Guests told by a doctor not to exercise cannot join. Pregnant guests cannot join lava-stone hot yoga; room-temperature maternity yoga is available.

The studio also offers room-temperature yoga, women-only kickboxercise, boxercise, HIIT and personal training, with more than 25 kinds of yoga lessons. Many of our yoga instructors speak English, and the studio’s owner often helps guests from the US bases in English herself.

For a yoga visit, the trial lesson is 60 minutes and costs ¥1,980 including tax. It includes 2 bath towels, 1 face towel and mat rental. Consult the prices page for costs and the trial booking page to arrange the yoga trial. When planning around Pilates, check the studio information for the activity you want to attend.

References

1. Pilates for Overweight or Obesity: A Meta-Analysis — Yi Wang et al., 2021, Frontiers in Physiology. DOI: 10.3389/fphys.2021.643455
2. Effects of Pilates Programs on Body Composition, Flexibility, Muscular Strength, Balance, Functional Performance and Respiratory Function in Adult Women: A Systematic Review and Meta-Analysis — Čedomir Bajčetić et al., 2026, Sports. DOI: 10.3390/sports14090407
3. Effects of the Mat Pilates Method on Body Composition: Systematic Review With Meta-Analysis. — Allysiê Priscilla de Souza Cavina et al., 2020, Journal of physical activity & health. DOI: 10.1123/jpah.2019-0171
4. Effects of protein supplementation during pilates training on body composition, core muscle endurance, and joint flexibility in trained women: a randomized controlled trial — Christina Karpouzi et al., 2025, Journal of the International Society of Sports Nutrition. DOI: 10.1080/15502783.2025.2472891
5. Pilates and multiple health outcomes: An umbrella review. — Meng Xu et al., 2023, Journal of science and medicine in sport. DOI: 10.1016/j.jsams.2023.03.011
6. Investigating the Effects of Pilates on Body Composition, Posture, and Psychosocial Parameters in Women With and Without Obesity: A Randomized Controlled Study. — Sema Arslan Kabasakal et al., 2025, Journal of physical activity & health. DOI: 10.1123/jpah.2024-0498
7. Effects of reformer pilates on body composition, strength, and psychosomatic factors in overweight and obese women A randomized controlled trial — Ozge Gokalp et al., 2025, Scientific Reports. DOI: 10.1038/s41598-025-09683-8
8. The Influence of Pilates Exercises on Body Composition, Muscle Strength, and Gait Speed in Community-Dwelling Older Women: A Randomized Controlled Trial — A. Aibar-Almazán et al., 2020, Journal of Strength and Conditioning Research. DOI: 10.1519/jsc.0000000000003790

Cover photo: A woman and a trainer use a ladder barrel in a Pilates studio. (Photo: Helderoliveira / CC BY-SA 4.0 / Wikimedia Commons)

Information as of October 2026. For your own health, consult a doctor.

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