What are your "trick foods" that contain a good amount of calories but are good to eat?
Cheese! Parmesan is 50% protein and 50% fat by weight. Almost all soups and stews can be improved in taste and calories by adding enough coconut oil
Second dinner. Eat your first dinner early, and then eat a lunch sized snack right before bed. When I was gaining, this usually consisted of a turkey or roast beef sandwich.
Know that I was almost never hungry. I ate on a schedule, and tracked everything I ate.
I struggle to eat enough calories as meals, so I make "fat shakes". Obviously you're gonna want to adapt this to your personal preferences, but: coconut milk and protein powder as your base, a little sweetener (stevia, sukrin), a litte salt, one avocado, a bit of peanut butter, and a banana if you're feeling wild.
I eat keto-ish... Olive oil, ghee, and coconut oils are all hugely calorie rich and can easily be snuck into food. Hellamns mayo is 700+ calories per 100g, so slathering it on some broccoli can quickly make up any caloric gap :)
Calorie restriction IS perhaps the healthiest route, if you are mainly interested in living longer. Feeling better is harder to quantify. The "TLDR" is: Exercise moderately, and find the minimal amount of calories you can consume without feeling like shit. That's the optimal balance.
The unfortunate reality is that often the "healthiest" path in life, doesn't FEEL the best. I felt my best lifting 3-4x a week, running, and eating 3600-3900 calories per day. I was constantly full, but felt like I had tons of physical and mental energy. Alas, plenty of research has been done on the effects of large calorie diets EVEN WHEN CONTROLLED FOR WEIGHT. Large calories = bad.
If you're interested, here's a good place to start:
1. Gummy bears. 500 calories a pack. (Usually before or after a workout)
2. Fritos, 1500 calories a bag.
3. Chicken breast and eggs - high protein and good fats from the eggs I can afford on a grad student stipend.
4. Natural peanut butter. This and other nut butters are key.
5. Whole milk.
Past a certain amount of carbs, I feel like they make me bloated, so it’s easier for me to use fats and some junk food to get the rest of calories in.