But the parent wrote "Does such caloric restricted diet allow one to maintain muscles and/or strength?" Which means he is asking about caloric restriction responding to comment about fasting.
I'd say the parent's question is perfectly valid: βHe gets by on one meal a day of 1500 calories.β implies, in fact outright states, a calorie restricted diet as well as a temporally restricted one.
But the parent wrote "Does such caloric restricted diet allow one to maintain muscles and/or strength?" Which means he is asking about caloric restriction responding to comment about fasting.