Increased weight loading reduces body weight and fat mass in patients with obesity, according to the results of a proof-of-concept randomized clinical trial published in EClinicalMedicine.
Although leptin has been recognized to have a major influence on energy balance and obesity, the effect of leptin treatment has been limited, which supports the presence of another homeostatic mechanism. The gravitostat — the concept of a loading-dependent homeostatic regulation of body weight and fat mass — was recently described in rodents by the researchers of the current study.
The same researchers aimed to investigate the effect of artificially increased weight loading on biological weight in obese humans. They evaluated the efficacy of using a heavy-weight vest (high load) compared with a light-weight vest (low load) in changing body weight from baseline.
The translational proof-of-concept study (ClinicalTrials.gov Identifier: NCT03672903) included healthy men and women aged 18 to 70 years with mild obesity (body mass index >30 and ≤35 kg/m2). Of 99 potential participants screened, 69 were included and randomly assigned in a 1:1 ratio to receive low-load or high-load treatment.
The heavy-loading procedure involved the use of a vest with a weight corresponding to 11% of the participant’s body weight and the light-loading procedure involved an identical-looking vest with a weight corresponding to 1% of the participant’s body weight. The participants were asked to use the assigned vest for ≥8 hours per day for 3 weeks. The primary outcome was the percent change in body weight.
Relative body weight loss after 3 weeks was significant in the high-load group (-1.68%; 95% CI, -2.09 to -1.27) but not in the low-load group (-0.31%; 95% CI, -0.70 to 0.08), and the mean difference between groups was statistically significant (mean difference, -1.37%; 95% CI, -1.96 to -0.79; P <.001). The results were very similar in the per protocol analyses (mean difference, -1.34%; 95% CI, -1.94 to -0.74).
The average absolute difference between groups in change in body weight was 1.31 kg (95% CI, -1.84 to -0.78). High-load treatment corresponded to greater reductions in fat mass (mean difference between groups, -4.04%, 95% CI, -6.53 to -1.55; P =.0019), but not fat-free mass (mean difference between groups, 0.43%; 95% CI, -1.47 to 2.34; P =.65), compared with low-load treatment.
No serious adverse event was reported in either group. Adverse events were more common in the high-load group compared with the low-load group (37.1% vs 16.2%, respectively), mostly secondary to musculoskeletal adverse events, including arthralgia, myalgia, pain in lower extremity, or swelling of the ankle and/or foot.
The researchers acknowledged several limitations to the study, including the short duration of the study and lack of blinding, as both the investigators and the participants could feel how heavy the selected weight vest was. Furthermore, the data on time using the weight vest was self-reported.
“[I]ncreased weight loading reduced body weight and fat mass in obese subjects in a similar way as previously shown in obese rodents. These findings demonstrate that there is a weight loading dependent homeostatic regulation of body weight, supporting the gravitostat hypothesis also in humans,” concluded the researchers.
Disclosure: This study was partially funded by the Novo Nordisk Foundation. Please see the original reference for a full list of authors’ disclosures.
Ohlsson C, Gidestrand E, Bellman J, et al. Increased weight loading reduces body weight and body fat in obese subjects – a proof of concept randomized clinical trial [published online April 30, 2020]. EClinicalMedicine. doi:10.1016/j.eclinm.2020.100338