Physique

Guess it would depend on your actual caloric intake vs your training intensity and duration. People can have a high carb diet and pleasing physique, but the calorie burn must exceed the calorie intake.

For sprint and Olympics, you probably don't need an high carbohydrate diet. Eat a healthy, well rounded diet and try to stay away from prepared foods, saturated fats and junk food.
For weight loss, the formula is calories in to calories out with a few dents here and there. If you want to lose weight, burn off more calories than you consume. Ignore the fad diets.

Exactly.
Eat good whole foods. Carbs, healthy fats and protein. I shoot for 40/35/25 split.
Generally take in less than you burn within reason (don't eat 200 and burn 2500 in a day). Aim for a pound a week for loss to keep it healthy and not go into catabolism.
AND YES, IGNORE FAD DIETS! Not sold on the keto, paleo, high fat... etc. It's not sustainable.

"Lean physique" is a byproduct of training for triathlons. Your real goal is optimal diet for best races. I've had lean physique using eggs, skim milk, and tuna as sources of protein. I've also had a lean physique eating a hamburger or two every day, and actually had better races. Animal protein for best muscle rebuilding, and there are some vitamins in fat. As others have said, moderation is key.

To answer your question, absolutely yes.

I had a dietitian explain it this way in regards to diets .: If you can't do for the rest of your life, then you shouldn't do it for one day. To be successful long term you need to follow a balanced diet in portions.that match your output level.

Fad diets do not work long term.

I had a dietitian explain it this way in regards to diets .: If you can't do for the rest of your life, then you shouldn't do it for one day. To be successful long term you need to follow a balanced diet in portions.that match your output level.

Fad diets do not work long term.

Thankyou for your input
At the moment I shoot for 60/20/20 so more Carbs, but so far this seems to be working fine for me