>he has a bias towards certain foods instead of viewing everything objectively
>certain foods don't objectively taste like shit
>Exposure, plain and simple. Scientists tell us that aversions fade away when we eat moderate doses of the hated foods at moderate intervals, especially if the food is complex and new to us. (Don't try this with allergies, but don't cheat either: few of us have genuine food allergies.) Exposure works by overcoming our innate neophobia, the omnivore's fear of new foods that balances the biological urge to explore for them. Did you know that babies who are breast-fed will later have less trouble with novel foods than those who are given formula? The variety of flavors that make their way into breast milk from the mother's diet prepares the infant for the culinary surprises that lie ahead. Most parents give up trying novel foods on their weanlings after two or three attempts and then complain to the pediatrician; this may be the most common cause of fussy eaters and finicky adults--of omnivores manqués. Most babies will accept nearly anything after eight or ten tries.
One you get down to the macronutrient level, nothing tastes bad, and you realize taste is all in your head (i.e. bias). Like, say, protein: your body needs a certain regular intake to maintain and grow cells and tissue. At the macronutrient level, there's no taste - it's all just protein broken down into amino acids and uptaken into the bloodstream.
And so taste really doesn't factor into it at all. Unless you want to eat, which means giving in to inherent instinct, strong dopamine response, and thus well-developed biases. Suffice to say, I don't trust a thing going on in my mouth and brain when it'd have me eating sugar and fat in chocolate form with too many shots of whisky over a well-balanced meal.
Some things naturally, objectively, factually taste bad. Black licorice, anchovies, fecal matter. Literally only animals/the mentally ill eat these. Just because some things are good for you doesn't mean your brain can just overcome an aversion to something. I bet you'd have no trouble eating raw cow balls on Fear Factor, since "mind over matter, bro."