Muscle Physiology and Nutrition
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1. Are the nutritional needs of slow-twitch, fast-twitch and heart muscles the
same?
No. Fast-twitch muscles, used in high-power exertion (e.g. powerlifting), use
glycogen (sugar stores in the muscle). Slow-twitch and heart muscles use both
glycogen and fat.
2. Is it true that fat is burned more efficiently than carbohydrate stores if
training levels are sub threshold?
At rest, you burn 5-10% of your calories as protein and 90 % as carbohydrate and
fat (split evenly between these two). During exercise the percentage of calories you
burn as protein stays roughly the same, but the split between carbohydrate and fat
changes. The percent of energy coming from fat decreases but the total amount of
fat burned still goes up since more calories are burned. However, over ~70% of your
maximum intensity the lowering percentage of fat finally wins out and the total amount
of fat calories burned goes down. The higher the intensity, the less the body wants to
use fat as a fuel source.
same?
No. Fast-twitch muscles, used in high-power exertion (e.g. powerlifting), use
glycogen (sugar stores in the muscle). Slow-twitch and heart muscles use both
glycogen and fat.
2. Is it true that fat is burned more efficiently than carbohydrate stores if
training levels are sub threshold?
At rest, you burn 5-10% of your calories as protein and 90 % as carbohydrate and
fat (split evenly between these two). During exercise the percentage of calories you
burn as protein stays roughly the same, but the split between carbohydrate and fat
changes. The percent of energy coming from fat decreases but the total amount of
fat burned still goes up since more calories are burned. However, over ~70% of your
maximum intensity the lowering percentage of fat finally wins out and the total amount
of fat calories burned goes down. The higher the intensity, the less the body wants to
use fat as a fuel source.
© Clyde F. Wilson