See it all over, online, on here, in real life.
People have to have three pretty substantial meals per day or they think they'll starve or not get enough nutrients.
A good amount of people, men especially, think a cold meal or salad based meal is not a real meal, or anywhere near enough to pass as one.
If it isn't huge, or hot, people often think it isn't value for money.
It isn't uncommon to hear 'rabbit food' or such when people choose cold or salad based meals.
Myself, I love both, and eat a warm meal most evenings, so don't have much of a horse in the race, but I do think it's a thing.
Not sure how other cultures go about it, would be interesting to find out.
Is it a UK specific thing, to always need a large hot meal several times per day?
A typical example is:
Porridge and berries of full breakfast english style etc for breakfast.
Baked potato with tuna, or salad for lunch, or soup with whatever and copious amounts of pulses.
Then cottage pie or something equally large for dinner.
Then, often, a later meal, give or take.
And a lot of us are still hungry after this, or snack in between, so WTF is going on!?