I doubt you’ll underconsume somehow… I’ve been exercising plentifully in past six days…mornings I’ve been cycling whilst fasted. I’ve then ensured I ate quite gently when I broke the fast on return from ride…maybe handful of fruit pieces plus three tablespoons natural yoghurt, and so been careful not to be tempted in to over-eating.
Late afternoon I’ve had a fistful size of protein (for me that’s a piece of beef steak, chicken breast, salmon fillet or mackerel) plus two fistsful size of vegetables or mixed salad.
I was doing same too before I came away on holiday whilst having alternate days either on weights or road cycling up to 58 miles. It’s a fallacy you’ve got to eat loads. You really need to ensure decent wholesome calories go in and not puff up to some high calorie-count you read somewhere by adding some crap calories like bread or cake.
If you eat packaged stuff with list of ingredients published on the back, basically it’s crap. If you’ve got any of the above mentioned proteins in a pack…the contents will be quite simple to understand! And a list of various fruits or fresh salad items, or vegetables don’t require lists of contents… they’re pretty obviously self-explanatory.
Fish contains fish. Chicken not in fancy cause contains chicken. Fresh mackerel contains mackerel. Beef Steak contains beef. Tomatoes contain tomato… there’s a pattern developing here, if you catch my drift. Good luck. Keep it simple. Oh, and await contradictions!