How do you measure insulin resistance?
There is no single best method for everyone: the clamp is the most accurate but is only feasible in a specialised setting. For practical use, HOMA or QUICKI from a fasting blood draw are a reasonable starting point, provided the result is compared against population-specific norms.
The most accurate method is the euglycaemic hyperinsulinaemic clamp. In this procedure, insulin is administered intravenously while blood sugar is kept artificially stable. The amount of glucose the body then requires directly reflects how sensitive it is to insulin. The method is the most reliable, but takes several hours and requires specialised equipment. One practical point to keep in mind: the result must be corrected for muscle mass, not total body weight, otherwise insulin sensitivity in people with excess weight will be underestimated.
One step less burdensome is the oral glucose tolerance test, in which you drink a sugar solution and then have blood drawn at multiple time points. An index is calculated from the glucose and insulin values, such as the Matsuda index. This provides a reasonable estimate of how the body responds after a meal, but is less accurate than the clamp. Mixed meal tests are also being studied increasingly often for this purpose.
In day-to-day practice, HOMA and QUICKI are more popular. Both calculate insulin resistance from fasting blood values, are inexpensive and straightforward to perform. QUICKI has been compared extensively with the clamp and also predicts the risk of developing diabetes later in life. The drawback of both is that they say nothing about how the body handles insulin after a meal. In addition, the cut-off values are not universal: they differ by age, sex and population group, so a 'normal value' that applies to one group does not necessarily apply to another.
The TyG index, calculated from fasting triglycerides and glucose, is even less expensive and in one small study (99 participants) showed reasonable agreement with the clamp. This is an interesting indication, but it is too early for broad use as a diagnostic tool.
All sources are reviews or one small clinical trial (n=99). No large randomised studies or meta-analyses are available on the diagnostic comparison of measurement methods. The strength of evidence is reasonable for the gold standard (clamp), but moderate for the practical indices.
What is insulin resistance and can I reverse it?
Insulin resistance can in many cases be substantially reversed, and exercising more combined with a healthier diet are the best-evidenced approaches for doing so. Starting early pays off, because the longer the vicious cycle runs, the harder it becomes to break.
What are the earliest signs of insulin resistance?
Early signs of insulin resistance are measurable long before a diabetes diagnosis: elevated fasting insulin, abdominal fat, abnormal blood fats, and excess fat within the muscles. If you have risk factors, have your fasting insulin measured, because standard blood sugar tests respond too late.
Does strength training help against insulin resistance?
Strength training probably helps against insulin resistance, although the effect is most strongly demonstrated in combination with endurance training and, for additional weight loss, changes in diet.
Does magnesium help with insulin resistance?
There is a reasonable amount of evidence that magnesium has a beneficial effect on insulin resistance, particularly if your magnesium levels are too low. If you are not in a risk group, it is sensible to first check whether you are getting enough through your diet before turning to supplements.
Which foods improve your insulin sensitivity?
Diet can clearly improve your insulin sensitivity. The Mediterranean diet has the strongest evidence base, but the timing and order of your meals also play a demonstrable role.
What does alcohol do to your blood sugar and insulin sensitivity?
The effect of alcohol on your blood sugar depends strongly on context: on an empty stomach the risk of low blood sugar is real, whereas with a meal it may temporarily rise instead. If you have diabetes or use blood-sugar-lowering medication, discuss with your doctor how to incorporate alcohol safely.