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5/2 Diet, Muscle Loss, and Scrawny Guys

I’m planning on running the 5/2 diet to lose some fat.

The diet calls for Mag-10 servings to avoid muscle loss, a big fear of many jacked guys. However, I am 165 pounds and 6 feet tall. I’m not totally without muscle, but should I be worried about losing it when there isn’t much there, or would this only be a concern if I were walking around with a bunch of extra muscle? Would the Mag-10 do anything for me?

I imagine from a physiological standpoint, if I were a lean 200, that’s a lot of muscle and my body might not want to hold onto it. Is muscle loss easier/more common the more of it you have?

Why are you trying to lose mass?


If you’re in a deficit AND you don’t meet your protein requirements through diet then I don’t care how little muscle you have, your body will shrink your muscle mass if it needs aminos (up to a point).

Have the protein

I’m a rock climber looking to get in alpine shape now that summer’s around the corner. I lift as well, but it’s a secondary hobby. My weight fluctuates from 160-175 throughout the year…always going for the lighter end in the summer time.

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How old are you?

If anything, that’s even more reason to focus on muscle preservation. When you’ve got 1/8 tank of gas, you turn off the A/C and hit cruise control to avoid sputtering out. When you’ve got 3/4 tank, it’s not as important.

Basically double your protein intake for those days from a very efficient source.

Pretty much. Muscle is metabolically expensive for the body to hold on to, so in true long-term fasting/starvation situations, it’s typically the first fuel source the body turns to. When dieting under controlled conditions, it’s still essential to prioritize muscle preservation for metabolic benefits, insulin sensitivity, and visible physique improvement.


As to your question, muscle loss during a fat loss phase is not the big issue people make it out to be. Continue to lift weights and eat at least 1g or protein per pound of body weight and you should be good. No need for a supplement like Mag-10.


I’m 27.