International Journal of Obesity (2010) 34, 1099–1100 & 2010 Macmillan Publishers Limited All rights reserved 0307-0565/10 $32.00 www.nature.com/ijo
LETTER TO THE EDITOR Does loss of gluteofemoral fat through diet and exercise deteriorate metabolic health? International Journal of Obesity (2010) 34, 1099–1100; doi:10.1038/ijo.2010.75; published online 20 April 2010
We read with great interest the recent review by Manolopoulos et al.,1 which reinforces the important notion that regional distribution of adipose tissue is a critical determinant of metabolic risk, independent of total adiposity. Indeed, abdominal adiposity, specifically visceral fat, is a strong predictor of health risk independent of other fat depots, and the reduction of visceral fat through diet and/or exercise is associated with substantial improvement in metabolic profile.2 Conversely, cross-sectional evidence suggests that gluteofemoral subcutaneous fat deposition may be protective against metabolic risk.2 However, in contrast to the authors’ assertion, the reduction of gluteofemoral subcutaneous fat may not always result in negative metabolic changes. As discussed by Manolopoulos et al.,1 the loss of gluteofemoral subcutaneous fat in pathogenic states such as lipodystrophy is often associated with metabolic deterioration. This reduction in gluteofemoral subcutaneous fat mass occurs via an unfavorable apoptosis of the existing adipocytes.3 In contrast, the loss of gluteofemoral subcutaneous fat among healthy individuals in response to a negative energy balance (as induced by diet or exercise) is a physiologically distinct phenomenon, as it occurs via a reduction in adipocyte size, while the number of adipocytes remains unchanged.4 Whereas loss of functional adipocytes in lipodystrophy is metabolically deleterious, the shrinking of adipocytes during negative energy balance is metabolically beneficial.5 The authors cite the study of Okura et al.6 suggesting that reduction in gluteofemoral subcutaneous fat in response to diet and exercise results in worsening of the metabolic status. Unfortunately, in that study, (1) dual-energy X-ray absorptiometry measurement of trunk fat was represented by the combination of abdominal and gluteal fat depots, which have inverse associations with the metabolic risk; (2) measurement of leg fat did not distinguish between subcutaneous and inter-muscular fat depots; and (3) the analyses did not adjust for the changes in visceral and abdominal subcutaneous fat. Thus, as we have previously argued,2 the limitations inherent to this study confound interpretation and preclude definitive conclusions regarding
the influence of gluteofemoral subcutaneous fat loss on metabolic status. In a follow-up study of 107 obese men and women with metabolic risk who underwent diet or exercise weight-loss treatment, we found no evidence of a negative effect of gluteofemoral subcutaneous fat loss on various cardiometabolic outcomes, including fasting lipids, insulin and glucose levels, and glucose tolerance.2 In fact, our results revealed that reduction in gluteofemoral subcutaneous fat, as quantified by whole-body magnetic resonance imaging, is associated with improvement in the insulin response during an oral glucose tolerance test. Although the wasting of gluteofemoral subcutaneous fat in disease states is correlated with worsening of the metabolic profile, the reduction of gluteofemoral subcutaneous fat through diet or exercise intervention likely results in metabolic improvement, much akin to that observed in response to reduction of adipose tissue from the abdomen. In other words, among overweight and obese men and women, the reduction of excess adipose tissue in response to negative energy balance is likely to convey health benefits regardless of the origin.
Conflict of interest The authors declare no conflict of interest. PM Janiszewski1 and JL Kuk2 School of Kinesiology and Health Studies, Queen’s University, Kingston, Ontario, Canada and 2School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada E-mail:
[email protected] 1
References 1 Manolopoulos KN, Karpe F, Frayn KN. Gluteofemoral body fat as a determinant of metabolic health. Int J Obes (Lond) 2010; 34: 949–959. 2 Janiszewski PM, Kuk JL, Ross R. Is the reduction of lower-body subcutaneous adipose tissue associated with elevations in risk factors for diabetes and cardiovascular disease? Diabetologia 2008; 51: 1475–1482. 3 Domingo P, Matias-Guiu X, Pujol RM, Francia E, Lagarda E, Sambeat MA et al. Subcutaneous adipocyte apoptosis in HIV-1 protease inhibitor-associated lipodystrophy. AIDS (London, England) 1999; 13: 2261–2267.
Letter to the Editor
1100 4 Bjorntorp P, Carlgren G, Isaksson B, Krotkiewski M, Larsson B, Sjostrom L. Effect of an energy-reduced dietary regimen in relation to adipose tissue cellularity in obese women. Am J Clin Nutr 1975; 28: 445–452. 5 Larson-Meyer DE, Heilbronn LK, Redman LM, Newcomer BR, Frisard MI, Anton S et al. Effect of calorie restriction with or
International Journal of Obesity
without exercise on insulin sensitivity, beta-cell function, fat cell size, and ectopic lipid in overweight subjects. Diabetes Care 2006; 29: 1337–1344. 6 Okura T, Nakata Y, Yamabuki K, Tanaka K. Regional body composition changes exhibit opposing effects on coronary heart disease risk factors. Arterioscler Thromb Vasc Biol 2004; 24: 923–929.
