Of course, the general idea is to lose excess fat that isn’t contributing anything to swimming, biking and runnning…and in fact gets in the way, since the extra weight makes you slower…particularly in running, and going uphill on the bike…and not sport specific muscle, which is contributing to the effort.
As a side note, many authors make the point that restricting calories too much can lead to your body adjusting by reducing your metabolism, which makes it even more difficult to lose weight…makes sense…don’t give it enough energy, and your body will slow down to a point to match the intake…many stories are cited where nutritionists ‘increase’ calories, to reduce weight…but we digress for this post…look for that discussion in a future Post.
So how about that fat loss vs. muscle loss…like most things nutrition related, the answers are often contradictory.
There are also some authors that point to the ‘type’ of workouts…some say slow and long burns fat…some say fast, intense…and some say that weight training is the way…sigh…_another_ topic for another day.
The one thread that seems to hold true in my reading, is that keeping your exercise volume up, and protein levels up, gives you the greatest chance of reducing unnecessary fat, instead of desirable muscle.
Joe Friel, in an article in 2008, acknowledges that definitive studies on the topic for athlete’s are thin…and cites one in 1994 that leans towards maintaining protein as you reduce calories:
It appears that when calories are reduced to lose weight, which is more effective than increasing training workload, the protein content of the diet must be kept at near normal levels. This, of course, assumes that you’re eating adequate protein before starting the diet, which many athletes aren’t. If your protein intake is low, typically less than about 20 percent of total calories, then training quality will suffer and you are likely to lose muscle mass when eating less.
Monique Ryan, in Sports Nutrition for Endurance Athlete’s, also highlights the protein element, and notes that in her opinion, athlete’s that are restricting calories should be consuming .8 – .9 grams of protein per pound of body weight (so for me 160-180 grams)…the same as she recommends for athletes that have a ‘very heavy training’ schedule, and double her recommendation for those that are only training moderately (.45 or for me, 90 grams).
Matt Fitzgerald in Racing Weight, also likes protein…up to 30% in the off-season, largely for reducing appetite and other benefits, although he cites a study that says 12-15% of protein is fine even for strength athlete’s, and another study, (Rennie and Tipton 2000) that concluded that:
whole-body protein synthesis achieves its maximum rate at a protein intake level of 1.4 grams per kilogram of body weight (3.1 grams per pound…for me 62 grams) of protein. (Dad note: In other words, anything more than that isn’t needed)
So, if you want to lose some weight, and would prefer it to be fat instead of muscle, calorie reduction is at the core, and there appears to be a benefit to exercising and keeping up the protein. It feels logical to me, that if your body adapts to how it’s being utilized, that continuing to swim, bike and run should tell it which muscles I’m using, and therefore to leave them alone…or more properly I’m betting that the body’s drive to repair them after exercise will equal or exceed the desire to cannibalize them to cover a calorie shortfall…let it look to excess fat stores that will happily give up their stored energy without other body systems fighting to keep them…and I keep the calorie shortfall small enough that my body shouldn’t be going into some panic mode to make adjustments…200-400 calories a day…barely noticable…go get it from the fat.
In terms of protein, how much?…for me, I keep it nudged up closer to 20%, than to 10-15%, and therefore added in a 2nd scoop of SP Complete (protein) in my morning smoothie to help get it in…also see our section in this blog on:
Oh…and you’d need to be tracking it to know what your levels are in the first place 🙂
Last few days by way of example, my protein grams and percentage…differences in grams on a daily basis is based on differences in total calories for the day…I may still nudge that up a bit closer to 20%, although with exercise coming back on stream, the total grams will naturally come up as I eat more calories, even if I stay in the 15-20% range: