I ate a blueberry scone today. I normally don't eat sweets, but I've been walking about 5 hours a day seeing sights and temples, and I realized I was only eating like 1800 calories. So, that ain't good. The only high calorie item at Starbucks, so I got the scone. It tasted great.
And I thought about it. Why does the scone taste great, when healthier stuff doesn't?
Answer: Because our taste buds don't suit us well in the modern day. The reason junk food tastes good is because it was advantageous in the past. Sweet things, high density carbs, and fats were really efficient for surviving and not poisonous back then.
But now, they're not the best way. The taste buds evolved to help us survive, but now they're kind of not helping. It's like a broken speedometer in a car. Foods are supposed to taste good to let you know that they're safe and beneficial to eat. But now, we don't get poisoned from toxic plants... we get poisoned from too much refined sugar with diabetes and obesity and such.
It'd be like if you were watching the speedometer in the car and it said "65" on the freeway, but you were going 110 in reality. Eating off what your taste buds tell you is bad for your survival now.
And that sucks, because taste is a really, really powerful thing. But taste's original function - survival - has been subverted by the modern world.
Me? I want to eat 99% of the time for survival, which means fiber, complex carbs, lean protein, and good fats, and not too much junk. That scone sure did taste good though. It's like my body was saying "that's the perfect speed" whereas the car was actually heading at a wall at 110 miles an hour.