Let’s say one Saturday you decide to go to Denny’s for breakfast and have their smoked sausage slam (1480 calories, 88grams fat, 30grams saturated fat, 4,430mg sodium, 610mg cholesterol,118g carbs). Then for lunch you decide to go to Outback and have their Steakhouse Aussie Cheese Fries (2900 calories, 182grams fat, 240g carbs) and their Chocolate Thunder from Down Under (1220 calories, 78grams fat, 130g carbs) for dessert. Then at dinner time, completely unaware that you’ve already consumed way more calories, fat, cholesterol, carbohydrates, and sodium than any single individual should eat in a day, you consume 4 slices of meatlovers pizza from pizza hut (1360 calories, 76 grams fat, 180mg cholesterol, 152 grams carbohydrates).
This might sound a bit extreme, but it’s not very difficult to surpass the daily quantities of calories, fat, cholesterol, carbohydrates you’re allowed. All it takes is not paying attention to what you’re eating. You could bypass your daily allowances in a single fast food meal so that, even if that is the only meal you consume for the day you can still gain weight. You might insist that you only had one meal but if that one meal was a deadly plate of food with more calories that you can possibly burn in a day, more fat, saturated fat, cholesterol, sodium than your body needs, it will make no difference that it was your only meal.
Caring for your mind and body requires being aware of what you’re putting into your body and how it’s going to affect your in the long run. In the short term it might taste good to eat but in the long term it keeps you fat and depressed and filled with self-hate.