Does diet really matter much for anything in your experience?

Calories held constant, I feel fuller and perform better off a healthy diet. Sure I can eat 2000-2500 calories worth of candy bars and still lose weight, but I'll feel like dog sh*t.

I have never ever felt dog sh*t. What does it feel like?

I eat "on the healthy side of normal". That means that nothing is forbidden, there are no hard fast rules. I eat what I like, I just dont over eat and I dont over indulge on calorie dense low nutrient foods often. I am a social drinker so that means at most I might have a few beers twice in one week, most weeks that is only on a friday or sat.

People on this site get all twisted over diets but I dont get it. Eating is one of few pleasures in life completely cutting out huge swaths of foods just seems so limiting.

Sure, obesity and chronic illness have tripled in the last 40 years because of a stealth genetic mutation, not because of the avalanche of processed fast-food crap flooding every venue and retail outlet.

There's as much value in obsessing over diet as there is in chi running.

OP, how old are you? The older I get the more important diet is, and I suspect was as issues arise that are most probably diet related. A poor diet often catches up on us, not all the time but often.

A poor diet always catches up to you. Some hit this wall later than others, but it is undefeated.

Although people often talk about such health problems, most pay little attention to it.

Having proper iron was the difference between not breaking 17 and qualifying for NXN for a teammate of mine.

Exactly and well said. A bad diet long term catches up on you. Hence all the people dying from heart disease, cancers, strokes etc later in life. Yes some of it can have a genetic element but how you look after yourself long term is much more important

Yeah, but to his point, if you only at 1500 calories per day of processed fast food, you wouldn’t be obese. People eat 4000-5000 calories per day to get there, mixed with very little active calorie burning.

Yes, I think a healthy diet is important as you age. Digestive issues seem to be the main issue for me when I eat poorly for an extended time period.

Overall I eat fairly healthy, don’t drink alcohol anymore. I get fast food once per week with the kids (either a McDouble at McDs or a Spicy Chicken sandwich at Chick-fil-A). I don’t order fries and get an unsweet tea.

Get your macros and take a multivitamin. Keep the processed stuff to a minimum but it’s okay to splurge, especially after a hard workout.

When you get older it does. When I was younger, training more and harder, I ate whatever you put in front of me. Whole bags of cookies, a dozen donuts, a whole box of cereal for breakfast.

As I got older I noticed that I "feel" it when I eat poorly.

Unfortunately it does. It's easier to fully embrace eating well than to do it grudgingly, although it's not always easy to maintain for long periods.

The problem with diets is that you don't see any results early on.
I assume the OP is pretty young 16-25 maybe. He can eat badly for a long time. It won't matter too much for race performance. BUT after 35-40 or so that will change.
Real results from eating you will see decades later.

As always I recommend looking into Ryp Essyelstyn's: Engine 2 diet and or watch Gamechanger.

Forties. I mostly tend to think like you as well, but am also skeptical because insisting that the cause-effect relationship takes a lifetime to manifest also makes it practically infeasible to conduct randomized controlled trials (as opposed to correlative epidemiological studies) to ascertain cause-effect of diet as opposed to genetic or lifestyle factors.

Wouldn’t our bodies have evolved to show nearer-term ill effects to dissuade “bad” eating instead of quietly deteriorating and presenting an insurmountable bill of damages at 73 for all the gluttony sins of a lifetime?

Great, like how exactly? Headaches next day? Fatigue? Fever? Pain? How confident are you in your attribution of such “feel” to diet?

Unfortunately no they haven't. It is just like cancer not causing pain until it is too late or nearly too late.

"A bad diet.." That is certainly open to interputation.

Each person has a different idea of what that is. Years ago we were all told to load up on carbs and cut out fat, so every thing was low fat this, low fat that, then they reversed that, so we got low carb cookies, low carb bread...

In the 80's-90's for some reason people thought bagels were a "health food" (I guess as opposed to a biscuit?) You were mocked for eating bacon and eggs for breakfast... now that is seen as a healthy source of protein and fat!

I can't speak for runn, but if I eat processed foods like crackers, cookies, many desserts I feel lethargic and pain in my joints.

If I drink chocolate milk, certain alcohol, or have tomato sauces I feel the effects of reflux in my esophagus and stomach.