How to get accurate cholesterol and blood glucose test results

Quick diet fixes won't help your cholesterol or blood glucose level

Published: March 08, 2015 06:00 AM

Q. I have a cholesterol test and blood sugar test scheduled soon. Should I try to clean up my diet in advance?

A. No, that deceptive tactic won’t work. A short stint of “clean eating” doesn’t have much impact on your blood work. It takes two to three months of healthy eating to see meaningful changes in LDL and HDL cho­les­ter­ol or in your HbA1c, a measure of long-term blood sugar levels that doesn’t require fasting. That’s according to Consumer Reports’ chief medical adviser, Mar­vin M. Lipman, M.D.

Instead of trying to make your numbers look good in the short term, make long-term changes for better health. One great way to start is by getting at least five servings a day of a wide variety of fruits and vegetables. They contain a multitude of potentially helpful nutrients, and studies consistently show eating plentiful amounts of produce reduces the risk of heart disease, high blood pressure, type 2 diabetes, and other chronic health problems. (Need some creative ways to beat veggie boredom? Check these ideas out.)

By the way, if you’re scheduled for a cholesterol test or blood sugar test that requires fasting, be sure to refrain from food and liquids, except water, for 9 to 12 hours beforehand, or your blood sugar and triglycerides will be higher than they really are. Avoid strenuous exercise for 12 to 24 hours before the test, too. Some evidence suggests that it can falsely increase HDL cholesterol levels.

Learn more ways to improve your cholesterol and control your blood sugar levels.

Editor's Note:

A version of this article also appeared in the December 2014 issue of Consumer Reports on Health.

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