Standard health checks are often outdated and many health pro's advocate for changes to these.

An example is the amount of people needing to be screened earlier in their 40's for certain cancers but current guidelines recommend checking at 50yrs+, think of LDL research indicating that what the cholesterol particles LOOK indicates how harmful they are rather than just presence in lipid profile.
GP's are prescribing statins to people who may not need it and dismissing people who have cancer in their 30's 40's because they are deemed 'too young'.

Our environments and lifestyles have changes much faster than any public guidelines do.

Technology and research advances but large organisations, governments etc are slow to act on things for a myriad of reasons (some legit & others less so).

I bring this up as many of us non experts rely on these guidelines filtered through our Dr's but too often we forget that they are just standards and rough guidelines.

Our genetics & environment, individual makeup determine what we must do INDIVIDUALLY and often the medical system isn't geared to suit that.

For some, very low carb diets are not good for them, for some veganism is not good. Lack of knowledge can cause damage due to people not understanding the diet they've chosen and eating unhealthy within a diet ethos (think bacon fest low carb or processed meat replacements & potato chip vegans) Or not factoring in medications, supplements.

We run the risk of flying a bit blind as tests that can provide more insight are costly and in some ways an expert is like "don't bother testing, there are plenty of ways to tell if you have an intolerance, insulin resistance etc" However I would argue that for many the knowledge you have X means quite a bit more in terms of motivation to change, gaining control.

Lots of things can be explained away and this idea of not testing because you can tell from other things and basically start eating better and things will improve completely misses the mental gymnastics people play in order to just get by on whatever's going on for them. It doesn't take into consideration that people who have intolerances are treated as "yeah right" from peers but also other health pro's because there is no diagnosis and also the metrics for the diagnosis might be out of date leaving out many people suffering. So not only are people being discouraged to seek out knowledge but are also then punished for not uh…knowing.

There is just too much "she'll be right" "do this because I say" "you don't need" etc lots of assumptions and its not helpful. It takes away even more of the instincts and confidence people have over their health as its just one big "maaaaybe"

(Not to mention it allows more room for saboteurs, emotional eating, food addiction to flourish)

So what can be done?

Contact pros in the field you need help in.

I'm a broken record when it comes to "go get blood tests if you haven't had any in the last 3 months" but there is also genetic testing.

NOW there are plenty of cheap-ish genetic tests usually marketed towards weight loss I'm not convinced these are super useful as the ones that show example reports don't show what variants you have, limited info.
*Edit! 2024 please be wary of privacy and companies like 23&me that have had huge breaches of privacy & data.

However you may be able to take the raw data to a professional. You want a test that gives you the raw data & reports that include the variants.