That's too vague. You can't just handwave and say 'better food' and 'junk food'. For decades junk food was thought by many as food with lots of fat instead of lots of sugar.
Going on any sort of diet sort of controls all that, and makes the person more vigilant of what's going into their body. So going from consuming wildly more than 2k calories a day, they might be consuming something closer to what their body actually needs, or less even. Metabolism catches up, and if the person is dieting, then they usually tack on some extra exercise too and that further helps their overall health etc.
Not true.
You don't need sugar, salt, and fat for food to taste good.
You also don't need to eliminate them for food to be healthy.
I'll believe it when I see (taste) it. In a context where I'm not socially forced to pretend.
All these things taste great all by themselves. Some need the proper application of heat, some don't. Some taste great BOTH ways.
*One super helpful thing to know is how food reacts to heat. for instance... sugars carmelize, intensifying sweetness. If you've only eaten perfectly ripe peaches raw... yes, you've had one of the worlds greatest treats, but you're missing out on what a grill can do! (cut in half, lightly oil the surface, place on low grill for a long time :-) Sweet potatoes? Man... stick one of those in a 425 oven for over an hour. (place directly on rack with tin foil on rack below to collect juices) Comes out sweet as candy. No additives needed.
If it sounds like I'm obsessed with good food... I am! I guess I'm just unusually lucky to like vegetables.
Check out this guy for inspiration: kenji alt lopez https://www.seriouseats.com/the-food-lab He's no health nut. He's just serious about good food.
Don't expect to win a taste contest, though.
Do yourself a favor and start learning how to cook. I took a week of vacation and went to a cooking boot camp. It was great.
It's certainly possible to make food badly at home, and often people do make taste sacrifices for nutrition, but it doesn't have to be that way.
Learn to cook and you have total control over the nutrition and taste of your food.
You can have BOTH!
The anticorrelation between taste and nutrition is real. Not universal, but real enough that "tasty and healthy" is a pipe dream used to sell cooking books and overpriced prepared food.
Want your couscous to taste good? Add salt and fat. Want your veggies to taste good? Salt, fat, possibly a sear -- you can occasionally dodge this with an acid, but if you try to do that all the time the result is miserable (ask me how I know). Want your tomato dish to taste good? Sugar. These, of course, are absurdly broad generalizations, and any stage in this journey you are free to remove the sugar/salt/fat and cook health food, but you will tend to work a lot harder and still come up with less tasty dishes.
IME, everyone who has claimed to cook tasty+healthy and who I have subsequently had the chance to evaluate has sacrificed in one or the other while deluding themselves into believing they have achieved both. Not being a jerk, I smile and play along, but the facts remain.
As am I.
Perhaps the problem is due to the assumption that cooking with salt, fat, and sugar is unheathly. Used within reason, it's not. You also don't have to add salt, fat, and sugar to everything to make it taste good. Learning to use herbs and spices helps a lot with that. It's important to start with good ingredients too.
Take your tomatoes example. Sure, if you start with standard store bought tomatoes, you'll have to fix them. But get some nice heirloom tomatoes from someones backyard, cut thick with olive oil, a little salt and pepper, and basalmic? Fantastic. And theres a reason tomato sauce recipes start with onion... sweetness. No need for sugar.
I LOVE microwaved/steamed/boiled corn on the cob with or without salt or butter.
I will admit that I have one health related problem with all this food... portion control. Cause it's all SO good.
I agree: it's not. Eating healthy is about getting enough of each micronutrient (not typically a problem) and not too much macronutrient(s).
The problem is that people use questionable proxies for this. "McDonald's is bad," "Whole Foods is good," "home cooking is angelic mana straight from the heavens!" -- when in fact Grandma's potato salad with ranch dressing, cheese, and croutons probably has a substantially worse macronutrient profile than a BigMac, the pizza at Whole Foods probably isn't significantly better for you than the pizza at Domino's, and the seared + oil drizzled + salted veggies in a restaurant probably have about the same nutritional content as the equivalent you make at home.
I also agree about tomatoes: it is in fact possible to fix them with salt and fat instead of fixing them with sugar. You can definitely get a more intense tomato taste than the store if you water them less than a commercial outfit would. I'm not nearly as crazy for this as most people seem to be, though. Good for salads, bad for sandwiches, but not to a degree that ignites my passions either way. "Heirloom" status is completely beside the point, except as advertising, for which it is solid psychological gold.
> I LOVE microwaved/steamed/boiled corn on the cob with or without salt or butter.
Yeah, because it's a sugary vegge-grain-fruit and sugar is good even without salt and butter. Of course, put some salt and butter on there and you have the holy trinity, which is downright delicious!
I'll admit to a lazy use of "heirloom" as a replacement for "not-ruined-for-the-sake-of-looking-good-on-a-shelf".
If you process your food yourself, you're unlikely to have the industrial equipment necessary (and you probably won't dissolve dozens of sugar cubes in a glass of water to make a drink), so food cooked from fresh ingredients is more likely to be healthy.
That's actually something I have been thinking about. When I read the sugar content of a lot of soda, bottled teas, milk shakes and others I wonder how they actually do manage to get that much sugar into it. When I put 13 teaspoons of sugar into a drink, it barely dissolves and is so sweet it's undrinkable.
You'd be surprised what some recipes for 'home cooked food' calls for. My SO and I have been on a global culinary 'adventure' in our kitchen for the past few months and we are constantly having to ignore when recipes call for cups (with an 's') of sugar for things like stews, breads (not cakes..), etc. While food cooked at home can be healthy, it's important to understand that not all food cooked at home is healthy.
And more to your comment: you've obviously never had homemade southern (US) sweet tea, which is basically a bucket of sugar with a bit of tea added for flavor.