Tuesday, April 12, 2016

Fasted Training and HMB

As an intermittent faster I often will throw some fasted training into my activities to assist with fat loss. It helps eliminate stubborn fat, especially that tissue found around the mid section of men and the hips and thighs of women. In layman`s terms the lack of insulin production while in a fasted state and the increased blood flow to the abdominals results in improved fat burning. The science is broken down quite well here.....


Fasted Training and Me

I prefer fasted training when planning any high intensity interval training (HIIT) first thing in the morning. It usually is RPM spin classes on Saturday and Sunday mornings during the Winter.
During the rest of the year I frequently bike commute to and from work fasted. On the ride home on those commutes I am usually at the 17 hour fasted mark. When will your body start breaking down muscle? I suspect everyone could be different but a logical assumption is muscle breakdown would ramp up the longer the fast continues. The question remains whether there is a "tipping" point and at what point your metabolism begins to effect muscle?

That is the tradeoff....fasted training could (potentially) result in muscle breakdown and loss, especially if one is leaner and trains fasted more often over an extended period of time. For those who are overweight or obese it seems this is less of a concern. Fasted training will burn mostly fat and muscle loss is limited in those individuals. As one becomes leaner the increase in muscle breakdown could increase.....

"It’s only as you get leaner that the proportion of lost weight coming from muscle tissue starts to rise.....the less fat you have to lose, the more “attention to detail” you’ll need to pay to stuff like protein intake, strength training and the size of your calorie deficit."

Begs the question - how to maximize fasted training fat burning but limit potential muscle loss?

There are a couple strategies that can help. By limiting the time spent training in a fasted state can limit muscle breakdown. Shorter high intensity work over longer steady state. I`m essentially doing that now as most of my fasted training( spinning) rarely exceeds forty five minutes in duration. My bike commute home is only five kilometres on average but is generally all uphill and challenging. Its short in duration but hard in effort.

The other option is HMB supplementation.

"β-Hydroxy-β-methylbutyrate (HMB), is a leucine-derived metabolite and has been found to have potent anticatabolic properties.  When leucine and HMB were compared, it appears that leucine performed better in muscle protein synthesis but HMB performed better in preventing muscle protein breakdown."

Essentially HMB does not help build muscle as previous claims suggested but it does effectively help maintain muscle. In terms of fasted training some HMB usage before and during could limit/ prevent muscle breakdown.

HMB also does not cause an insulin response(unlike BCAA`s) so pre workout supplementation would not end the fasting state.

"HMBs’ proven ability and superiority at reducing muscle wasting makes it an ideal supplement for maintaining lean muscle mass while trying to burn body fat...."

Postscript- I`ve picked up some HMB capsules(500 mg) and will begin incorporating it on fasted training days. Worth giving it a try (on a temporary basis) to see if it helps me achieve BMI % improvement while maintaining my current muscle mass. I'm my own best test dummy. Worse case scenario is I'm out some coin. Best case is I continue to drop weight closer to my goal (200 lbs) without losing muscle.
FYI - I am also increasing my strength training by lifting heavier more frequently and using whey isolate powder to ensure I get sufficient protein during my daily eat windows.


Anonymous said...

How effective was HMB as preserving muscle while fasted training?

XXX said...

The real question is whether or not HMB stimulates mTOR and therefore represses autophagy. I've been trying to find out and can't get any answers. If it does than one of the most important benefits of fasting is sabotaged; if it doesn't than HMB is a fasting essential for all those like us who train and want to preserve our muscle mass while fasting.