The so-called "authorities" on health all admit that half of all adults are metabolically compromised (in terms of insulin resistance) with most of those over 65 being in this situation.
Being metabolically compromised places you at a materially higher risk of diabetes and heart disease. These are diseases that may kill you, but even if they don't they are debilitating. Obesity is a big part of that; you can't run, you can't move, you wind up with joint replacement surgery as you age (which has to be re-done every 10 or 20 years and is major surgery) and, if it gets out of control it can and will lead to amputations, blindness and ultimately kidney disease and dialysis.
This is a miserable way to live the last 20, 30 or 40 years of your life and it's not a pleasant way to die either.
Most people will say "well, I have no symptoms and my doctor is ok with what I'm doing", so they'll ignore the possibilities here. This is extraordinarily unwise as the damage that causes these diseases happens over years or even decades before clinical disease (that sends you to the doctor) presents itself.
It is easy and inexpensive, however, to know if that damage has accrued to the point that some detectable signs are present. You can do it at home, and you should because once these markers get into your medical chart they never go away and while people may think they're protected by Obamacare right now until and unless we deal with the medical monopoly situation in this nation you are risking financial ruin without cause if those markers get into your chart even if you reverse the damage.
What happened before Obamacare and will happen if and when it collapses? If those markers are in your chart you may become completely uninsurable at any rational cost. That means that any major medical emergency instantly bankrupts nearly anyone.
As an aside I'm going to make an assumption here: You're not diabetic today (diagnosed.) If you are diabetic then none of the below is news to you in terms of testing as you already have these results over time since they're part of what your doctor has you doing already. Nonetheless, you might be shocked at the improvement from the below eating pattern changes, so keep reading -- just ignore the testing thing, as you're already doing it.
This is something you can do in the privacy of your own home with nobody but you having the results. You can then change your behavior, specifically, what you do and do not eat, if you have a deteriorating situation and see if it improves. There is little cost to this, essentially zero risk over the time involved and if it doesn't work for you or if you think I'm a crackpot (I don't have an "MD" after my name, after all) you will have lost nothing other than a few dollars that were spent on something you probably ought to own anyway, one of which is not consumed.
You're going to go buy two things:
1. An A1c test kit. WalMart has them and they're under $30. There are two tests in the box, so each is about $15. No, one isn't for your SO, spouse or kid -- they're both for you. If you have two people to check buy two. These are consumed and tossed when used up.
2. An inexpensive glucose meter and a box of lancets. Buy one of the models with inexpensive strips; the meters are all cheap (~$20 or so) but the strip cost varies widely, by as much as 500%! While you're not using this for diabetes monitoring this is a device that will last years if not a decade or more so strip cost does matter, although not nearly as much. Again, WalMart has a wide selection -- IMHO make yours based on the strip cost (lower is better) and choose one that has individually-wrapped strips (this way they do not deteriorate by having a bulk package opened, since you are not using these multiple times a day as a diabetic would.)
When you get home open up the A1c kit, read the instructions (yes, you have to follow them to the letter to get good results) and run one. Keep the second. Write down the result.
The ADA and "some" docs say any A1c number under 6.0 is ok. You want a number at or under 5.6%. Note that these kits as with all tests, including lab tests, have an error band to them which means that one test provides decent information but you need to check it as the actual number could be a few tenths to either side of the displayed result. Don't use the second test immediately (unless the first errors out due to a mistake on your part); you'll use that a month or two down the road to both check the error band (the odds of a random error going the same way twice is 1 in 4 instead of 1 in 2) and your outcome.
Be aware that there are some confounding factors with the A1c test. First, it "assumes" blood cells live three months. We know this is not always true; people with severe metabolic damage tend to have them live for less (which means the number reads low) and those without said damage tend to have them live longer (which means the number reads high) since what A1c measures is the percentage of glycated hemoglobin in the blood. Further, if you have some conditions, among them anemia (in particular) it will read low because in that case hemoglobin is below normal levels -- this is a particular risk for women who don't get enough iron in their diet although there are other causes. This probably won't change your test result enough to matter, but it is the reason that standing alone an A1c test, while good and in fact an essential checkpoint, isn't enough.
Next, you're going to do two different checks with the glucose meter. The first is a fasting test, which is done when you first wake up in the morning before eating or drinking anything other than water. Most meters will store some amount of history but again, write it down. If your number is under 90 but greater than 50 that's ok. If it's under 50 test it again -- a persistent result under 50 is an indication of hypoglycemia (low sugar) which is dangerous as levels below 40 can cause you to pass out (and if nobody finds you and deals with it you can die), so if you get a confirmed reading under 50 consider obtaining medical advice. Again, the ADA and some docs say anything under 100 is ok. Correct clinically but wrong for the purpose you're intending here. If you get a number over 90 do it again the next day; if you get a second reading over 90 you've got a potential problem.
The final thing you're going to do is wait until you eat a "normal" meal at home (whatever that is) but it should include a decent amount of carbohydrate. "Decent" doesn't mean carb overload, but it does mean roughly the equivalent of one cup (cooked) of rice. If you eat low-carb normally, this is your chance to eat something you usually don't. Test your blood sugar level before eating, then test again both one and two hours after eating. Write down the results; no relying on memory here. You should not get a result over 140 on either of the post-eating tests and ideally within two hours you should be back to where you were before consuming the meal. If you're not, take a third test at the three-hour point.
Now let's interpret.
If you are eating food containing carbs on a regular basis, your A1c is at or under 5.6 and your fasting glucose is under 90, neither of the one and two-hour post-meal readings exceed 140 and you are back to baseline within three hours you are probably ok metabolically at this point. This doesn't mean you don't have insulin resistance of some amount but at this point it is not manifesting in clinically-detectable harm to your cardiovascular system. If you are eating low-carb and have been for several months or longer your fasting glucose level may be a few points higher, anything under 100, and is ok provided the other two tests are both in-range. Note that if you are overweight you probably are metabolically compromised (an OGTT w/insulin assay would easily detect it) but the test is expensive and frankly, the mirror works just as well for anyone in this category: If you have a gut, you're metabolically compromised. Incidentally just because you eat low-carb you are not necessarily going to get a somewhat-higher fasting glucose level; I don't, for example, and I've been eating low-carb now for something like five years now but some people do. If you are eating low-carb and get a reading over 90 for your fasting glucose there is a decent chance you're doing it wrong; specifically, you may be eating far too few green vegetables in an attempt to go "very low or zero carb" and thus massively short on vitamin and mineral nutrients. It is possible to eat "VLC" and not have this problem but severe nutrient deficiencies play hell with hormone levels, so don't just blindly accept that an elevated fasting level is "ok" -- it's not, and it usually means you're doing something wrong and accumulating damage.
If your A1c is over 5.6 (but under 6.0) or your fasting glucose is over 90 (over 100 for low-carb eaters) or your first two-hour post-meal readings (either or both of them) go over 140 or you are not back to baseline within 3 hours you are accumulating metabolic damage that is doing material harm to your body. Your doctor will probably not detect this in his routine screen but if you ran the (expensive) OGTT w/insulin assay test, which your insurance will not cover in this instance since there is no clinical indication of disease, I'll lay a large wager it would show significant metabolic compromise with insulin levels perhaps as much as twice normal levels. You're at severe risk down the road even if you are not overweight and if you are overweight you're a walking heart attack or stroke unless you change what you're doing. More than half of all adults in the US and most people over 65 are in this category or one of the worse ones below.
If your A1c is over 6% or fasting glucose is over 100 (irrespective of what you eat) or either of the first two post-meal readings is over 160 (you almost-certainly won't be back to baseline within 3 hours in this instance) you're either diabetic now or shortly will be. Your doctor will be able to detect this in a routine screen; if he's honest he'll call it "pre-diabetes" and if he does your medical chart will be "branded" forever which, to the extent legal now or ever again, will trash your ability to obtain health insurance at a rational cost. You'll also get a whole raft of pills shoved at you, probably including metformin (to start) and a statin. That's the traditional thing for them to do but it may be both harmful and unnecessary.
If your A1c is over 6.5% or fasting glucose is over 130 or any of your post-meal readings are over 200 you are in trouble as you are almost-certainly clinically diabetic now. This pretty-much meets the "bright line" test in the medical establishment to call you diabetic. If this is the case your chart and impact on health insurance is irrelevant if you change nothing as it is a virtual certainty you will if not are suffering real, material and serious damage to your health. You're probably symptomatic too but denying it. It is your call what to do with that information but before you run to the doctor for a formal diagnosis and permanent branding on your medical chart, assuming you haven't previously been diagnosed, read the rest of this article.
If you're of both of normal weight and your results are in the first category then relax -- and in a year, or if you become overweight, do it again just to keep tabs on things.
But let's assume you are either (1) overweight or (2) your results are in any of the bottom three categories irrespective of your weight.
Try the following for a short period of time (4 weeks):
1. Stop eating sugars of any sort. If it says "sugar", "fructose", "sucrose", "corn syrup", "hfcs" or anything of the sort anywhere on the label do not eat it. No more cookies, no more chocolate, no more sugar in the coffee, no sugared sodas, etc. Just stop. No exceptions, no tapering down, stop.
2. Stop eating starches and grains. No more pastas or potatoes of any sort. No more bread irrespective of the type.
3. Stop eating anything containing machine-processed vegetable oils. No more corn oil, canola, rapeseed, etc. No cooking with any of these oils and yes, that includes peanut oil; the only exception is olive oil as a salad dressing (e.g. with vinegar.) This crap is in a lot of "food" and no amount of it is healthy. This means no more packaged foods in the general sense; no more boxed dinners, canned ravioli, "lunch pouches or easy-prepare things" and similar (those probably break all three constraints!), nothing that comes in a bag (other than frozen vegetables), etc. This also means no fried food of any sort prepared away from home since essentially nowhere fries anything in either tallow or lard any more (but they should.) If you like wings find a place that bakes them and order them with the dry rub instead of the HFCS-laden sauce.
These three rules above are absolutes. You'll be tempted to cheat, but we're talking about a month here. Just don't; you can do it, and you know it.
Now on to what you do eat.
4. Do eat all the green vegetables, whole, not canned or packaged, you want. Find something or a bunch of somethings you like such as broccoli, brussels sprouts, bell peppers, lettuce and similar. Whole, fresh or frozen (e.g. in a bag) are fine; canned or otherwise processed are not. Substitute these any time you would otherwise eat any sort of snack and keep eating them until you're not hungry any more. It's not impossible and it won't hurt you; in fact, they're all good for you. It is close to impossible to overeat if you're consuming green vegetables.
5. Do eat full-fat protein. Pork, chicken (skin-on, not trimmed), steak, hamburger (no bun; that's grains), fish, eggs, cheese, etc. No restrictions on any of these foods, but eat when hungry until you're not, not until "full."
6. Use spices, including pepper, cumin, etc. as much as you wish. Hot sauces typically contain zero sugar and are perfectly fine even in wild amounts (yes, Tobasco is ok.) This is a taste-based thing, of course, but anyone who thinks you can't toss on the Lowrey's or pepper the hell out of your steak is flat-out wrong. Not only can you use salt unless you are one of a very small percentage of the population that has a genetic intolerance to sodium restricting salt intake is worse than worthless in that electrolyte imbalances lead to cramps (especially if you exercise) and can be dangerous.
7. Be careful with legumes and nuts. These are generally ok but nuts are very high in caloric content and it's easy to wind up eating 3,000 calories worth of them in a few minutes! So if you want a few as a snack, go ahead; just don't eat them as a meal rather than as a snack. But do not generalize this to nut-based oils (such as peanut oil) or anything processed from nuts because you are then concentrating the bad without the balance of the good (see above in point #3.)
8. If you normally consume alcoholic beverages keep it to one per day on average and not more than two on any day.
9. Drink any time you're thirsty; water is of course ok, if you like coffee go right ahead. Cream is ok (not non-dairy creamer, actual cream that has to be in the fridge) but sugar is not. If you want sweetener use any of the non-sugar ones (we're not going to be a nazi about these for this purpose.) Diet sodas may be ok, but if you can avoid them do so.
Do this for one full month.
Now repeat the above tests. Note that A1c typically measures average blood glucose levels over about a three month time frame, so the change there may not be dramatic and in addition the error rate on the test may obscure the results.
But remember the above table; if you drop a category or approach doing so you have hard proof that you required no medication whatsoever to improve your situation and these results are individual to you.
In other words you didn't read something on The Internet by some kook (like me), you didn't take blind advice from some doctor or nutritionist (irrespective of how many letters are after his name) you ran an individualized test with objective results on your particular genetic and metabolic make-up and have a set of numbers before you that document the outcome in your particular body.
If the results show no change (or get worse) then you've lost nothing other than a bit of time and a few dollars. Over this short of a period of time no harm is going to come to you; the harm that comes from bad metabolic markers in this regard requires years of accumulation before it "gets" you. But if the results are either dramatic or trend the right direction (and if you actually do the above it's a good bet they will) you now know that it is possible to change those objective metabolic markers through near zero-cost measures that are easily implemented in your daily life without spending one minute in a doctor's office or taking (and spending money on) one single pill.
Is that enough motivation to continue for another month or two and see if you can return your metabolic profile to the top, that is, "ok" category?
Further, you just prevented yourself from being "branded" in your medical chart and you didn't do it by cheating, you improved your actual metabolic profile.
That ought to be plenty of reason to continue on that path and make it a lifestyle, considering that the difference between said improvement to the top category and any of the others is a very material change in your risk of heart attack, stroke, blindness, amputation, dialysis and death! Further there's a very good chance that at the same time you're going to see a change on the scale if you're overweight, and I bet you'll like that change as well.