Monday, May 25, 2015

More Aerobics, More Subcutaneous, Yet not More Visceral Fat Loss - Despite or Because of Higher Energy Intakes?

Visible abs require low subcutaneous, not visceral fat levels: Why? Well, despite being located at the midsection, the nasty fat covering your abs is subcutaneous.  
I should probably call today's SuppVersity article a "classic"; not because it was published in this form before, but rather because it is based on a paper that has been accepted for publication back in 1997. In view of the fact that the question its authors sought to answer is as topical today as it was in the late 1990s, though, I thought it may be worth writing a brief article about Takahashi Abe's quest for relationship between training frequency and subcutaneous and visceral fat loss in women (Abe. 1997). As Abe et al. point out, their study was "designed to investigate the effect of varying frequencies of aerobic exercise training and caloric restriction on [visceral fat mass] and [subc. fat mass]" (Abe. 1997).

In that, the scientists speculated that due to the increased energy expenditure the 13 women who had been randomly assigned to the 3-4 sessions per week group should lose significantly more subc. and visceral fat than their pendants who went to the gym only 1-2 times per week.
You can learn more about cardio at the SuppVersity

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Fasted Cardio & Beyond
During the complete study period subjects were advised to cut their energy intake by 200kcal/day and perform 30 min of medium-intensity cardio at 50-­60% of their individual maximal heart rate reserve (0.5≈0.6 [maximal pulse ­ resting pulse] + resting pulse) as calculated from a maximal exercise test. With the same baseline dietary deficit, the 3-4SW group would thus have a significantly more pronounced weekly caloric deficit than the 1-2SW group if all subjects stuck to their diets and their otherwise sedentary lifestyle.
Energy deficit - contribution of exercise vs. diet (Abe. 1997).
No diet = better weight loss? Now what is particularly interesting is that the high frequency training group 2-3SW did not not achieve the prescribed 200kcal (~15%) reduction in energy intake - and that despite the fact that the 3-4SW group only trained 2.8x per week (you see, adherence is a problem in scientific studies, too). If we do the math on intake vs. output, the 1-2SW group actually had a more pronounced deficit than the 3-4SW group. Against that background it's all the more surprising that they achieved a significantly more pronounced reduction in subcutaneous body fat (-16.2% vs. -4.9%) - even if we take into account that the calculations do not account for potential reductions of the basal metabolic rate in the dieting 1-2SW group.
As you already know from the headline, though, the expected difference showed only for the subcutaneous (that's the fat you actually see hanging around), yet not for the visceral (inter-organ) fat (see Figure 1) which was actually (non-significantly) more reduced in the 1-2SW group.
Figure 1: Changes in subc. and visceral fat over the course of the 13-wk study period (Abe. 1997).
Seeing that fat depots don't melt at the same speed is and was by no means news, though. And the difference doesn't exist for visceral vs, subcutaneous fat, but also for different subcutaneous fat depots.

Despres et al. (1985) for example found almost 2x higher rates of trunk fat vs. extremity fat loss in young men who lost 2.6kg of body fat over the course of a a 20­ wk aerobic exercise training program. Likewise in contrast to the results of the study at hand, a 9­ to 12­ month aerobic exercise training program on sedentary older men and women, that was conducted by scientists from the Washington University School of Medicine St. Louis showed a significantly greater reduction of upper trunk vs. extremityfat. (Kohrt. 1992).
So, do you do cardio to cut subc. and strenght to cut visceral fat? Both observations are mirrored in the study at hand, where the ladies lost sign. more SFM in the truncal segment compared with the limb segments, but they stand in contrast to the observations Treuth et al. made in a similarly designed study, in which the slightly older female study participants did yet not do 30 min of medium intensity steady state cardio, but rather upper and lower body resistance training.

If we compare the results of cardio (e.g. Abe, 1997, Kohrt, 1992) and strength training studies like the one by Treuth et al. (1995) from which I took the data in the figure above, it looks as if weights were the better visceral, while low-to-medium-intensity steady state cardio exercise the better subc. fat burner... well, on average.
With significant reductions in visceral (intra-abdominal), but only negligible reductions in subcutaneous fat, a comparison of the results of the study at hand with the Treuth-study does in fact suggest that strength training may have an edge over low(er) intensity steady state cardio when it comes to getting rid of the unhealthy fat in ones midsection.

What I would doubt, though, is that the same difference would be seen for resistance vs. HIIT or resistance vs. high intensity cardio training. Generally speaking, though, this difference appears to confirm another old bodybuilding mantra which is to combine intense strength training and relatively light, but frequent cardio training before stepping on stage. If we go by the results of the studies discussed in this article, as well as the STRIDE trial which shows reduced visc. fat with low volume and reduced visc. and subc. fat with higher amounts of exercise (Slentz. 2005), it does look as if high (not insane) volume cardio + high intensity weights was another reasonable bodybuilding practice.

And while the role of the total energy deficit still requires investigation it appears as if dieting would be the prerequisite to lose the unhealthy visceral fat, the extent of the deficit appears to be less important than exercise when the reduction of unaesthetic, but comparatively benign subcutaneous body fat is what you want to lose. One thing I can tell you without further research, though, is that the "last fat" is not going to go without a reduction in energy intake | Comment on Facebook!
References:
  • Abe, T., et al. "Relationship between training frequency and subcutaneous and visceral fat in women." Medicine and science in sports and exercise 29.12 (1997): 1549-1553.Despr├ęs, J. P., et al. "Effects of aerobic training on fat distribution in male subjects." Medicine and science in sports and exercise 17.1 (1985): 113.
  • Kohrt, Wendy M., Kathleen A. Obert, and John O. Holloszy. "Exercise training improves fat distribution patterns in 60-to 70-year-old men and women." Journal of gerontology 47.4 (1992): M99-M105.
  • Slentz, Cris A., et al. "Inactivity, exercise, and visceral fat. STRRIDE: a randomized, controlled study of exercise intensity and amount." Journal of Applied Physiology 99.4 (2005): 1613-1618.
  • Treuth, MARGARITA S., et al. "Reduction in intra-abdominal adipose tissue after strength training in older women." Journal of Applied Physiology 78.4 (1995): 1425-1431.