I am a believer in eating many times a day. Mainly to keep you sane.
Protien carbs,fat whatever stays in your body long enough to process. The only problem with 1 meal a day is stomach issues and a large as hell insulin spike which will most likely store a good ammount as fat.
Smaller insulin spikes keep ya lean in my opinion. When I'm gaining I eat 6 to 8 meals/day. Cutting is a different story because insulin can inhibit fat burning. Bigger spikes,less time insulin is present. I'm not a scientist and this may be bro science but it works for me