Having a good diet isn't in any way competitive with being up to date on your vaccines.

And a good diet absolutely will do something to prevent most infectious diseases - if your immune system is stressed/compromised due to a shit diet, you're much more likely to be infected when you're exposed. You're exposed to infectious disease constantly, and the reason you don't get sick the vast majority of the time is because you're successfully fighting those off.

I don't think he is arguing against vaccination or using modern medicine just that people see things like obesity and type-2 diabetes as issues that need to and maybe even should be cured with medicine or surgery while the actual answer is radical change in diet.

While I remain skeptical about long term effects of the new fad carnivore diet there is no doubt it has helped a lot of people with inflammation to regain control of their lives. You can look up Mikhaila Peterson's blog or interviews about the subject.

Why is this the actual answer? Most RCTs show the best obesity cure we currently have is surgery, and it wildly outperforms diet on an intention to treat basis.

Diets do terribly in long term RCTs.

What diet are they following? For how long? How is the adherence measured? Who has commissioned the study?

If you compare something like "the food pyramid" diet, but with less calories to surgery I have no doubt the surgery will keep more people at lighter weight after five years. However that doesn't seem like a fair comparison. For one the usual diet that gets pushed to fat people isn't a good diet to being with. Next one requires much more dedication than the other, meaning if you are going through a surgery to alter your body so you can't eat as much, then obviously the adherence will be higher.

Also people who result into surgery are usually on their last legs. Doctors won't give you the surgery unless it is your only option. So if you had to loose weight or die in next year, obviously the adherence will be a lot higher than with loose weight or in 10 years you will have to have a surgery.

All diet rct studies everywhere. There are no long term studies for diet that show weight loss in the same range as surgery.

Most weight loss diets are fine. They involving eating less food, particularly unhealthy food, and more healthier food. Keto, Paleo, Mediterranean, DASH. It doesn't matter because the differences between these diets aren't anywhere close to the differences between surgery and diets.

If you can find just one 5 year study that shows diet works anywhere nearly as well as surgery I'll change my opinion. But they don't exist. I've looked.

Treating the symptoms and not the cause.

Antibiotics, vaccines and a well-balanced diet are not mutually exclusive, nor did GP imply so.