People will be like ‘we have these correlational studies so you should change your entire diet to things your body doesn’t tell you are good and that bring you zero joy.’
I mean, seriously, f*** that s***. No.
I do buy that people have various specific nutritional requirements, and that not eating vegetables and fruits means you risk having deficits in various places. The same is true of basically any exclusionary diet chosen for whatever reason, and especially true for e.g. vegans.
In practice, the only thing that seems to be an actual issue is fiber.
“I don’t find this tasty” is not the same thing as “my body doesn’t tell me it’s good”, and this concept is at the core of many suboptimal fad diets, as well as a common blanket justification for being fat and unhealthy.
If you eat Krispy Kremes and pizza exclusively, your body will “tell you it’s good”. The whole reason people get fat in the first place is that the taste and satiety mechanisms we’ve evolved in an ancestral context are maladaptive for the modern hypercaloric, hyperpalatable environment.
If you eat donuts and burgers, and take a multivitamin to avoid deficiencies, I’d challenge you to crush, chew and savour the multivitamin on your tongue and see what your body has to say about that.
By omitting vegetables and fruits, you not only risk vitamin deficiencies, but miss out on the most under-appreciated aspect of whole plant foods: their phytonutrient and antioxidant content. Plants have an enormous array of complex, immensely beneficial and poorly understood compounds which interact with our bodies in ways that invariably prove immensely beneficial.
You can handwave the ubiquitously agreed upon benefits of fruit and vegetable consumption as “reliant on correlational studies”, but this is a major handwave indeed, and includes ignoring the strong mechanistic bases to assume this is almost certainly true.
Fundamentally, the obesity epidemic appears largely due to a mismatch between the body’s evolved hunger and satiety systems and the foods that have been created to wirehead them. Therefore, using “my body’s hunger and satiety systems tell me that eating XYZ is good” is very uncompelling.
A high VO2 Max is a superior metric. It is harder to achieve, and more predictive of health outcomes.
It’s possible and even somewhat common to have a low resting heart rate with a below average VO2 max, but it’s virtually impossible to have a high VO2 max and a high resting heart rate.