Why Lab Work Can Be Important for Weight Loss


By: Shanti Wolfe, Registered Dietitian

Lab work and annual check-ups with your primary care physician are an important part of keeping us healthy by keeping us informed.  Our bodies are very complicated and should get annual check-ups from a medical professional at least once a year utilizing lab tests.  Not only do lab tests give us an inside look at the body’s processes, but they can also help us identify what we need to do to lose weight. The most common lab tests measured are: CBC (Complete Blood Count), CMP (Comprehensive Metabolic Panel), and Lipids (cholesterols).  In this blog we will cover these 3 main lab tests and how they are useful for weight loss.

Complete Blood Count (CBC)

A CBC measures the composition of the blood that includes red blood cells, white blood cells and the amount of oxygen carried by the red blood cells.  Any type of anemia (as diagnosed by a primary care physician) can be a barrier to weight loss due to lack of oxygen to the working cells, and the lungs, heart, etc. (1).  Anemia can therefore effect weight loss because if the cells don’t get the oxygen in the levels they need, they won’t work as well, and won’t produce as much energy as they are supposed to. This can lead to a general level of fatigue.  Anemia can be diet related. Therefore, you should see a physician or medical professional who can help you determine if your diet is leading to your anemia.

Comprehensive Metabolic Panel (CMP)

A CMP test measures kidney, liver, digestive function and includes the electrolytes (sodium, potassium) and even measures fasting blood sugar.  If the kidney is not working properly, weight loss can be stalled due to insufficient removal of waste products.  Also, if the liver is not working properly, then hormones and transport proteins aren’t made as efficiently. This can result in the cells of the body not receiving what they need to function optimally.  If the blood sugar measures too high, your body might have trouble losing fat. The reason for this is because there is too much excess sugar (energy) that your body can’t use and stores for later (creating fat stores)(2).


A lipid test can measure cholesterol, triglycerides and helps a primary care physician to identify heart health.  Some people don’t respond as well to fats. Some people also don’t respond as well to carbohydrates and some people can’t properly digest and absorb proteins.  These lab tests help to identify how someone’s body reacts to certain macro nutrient splits. When a lipid test is coupled with some dietary history and the rest of the lab work, we can see why some people lose weight on low carb and struggle with weight loss on low fat and vice versa(3).

As you can tell from these common lab tests ordered by doctors, they can be helpful in figuring out what you need to do to lose weight based on your unique blood chemistry.

  1. https://www.ncbi.nlm.nih.gov/pubmed/24770833
  2. https://www.ncbi.nlm.nih.gov/pubmed/12972680
  3. http://annals.org/aim/article-abstract/716922/use-metabolic-markers-identify-overweight-individuals-who-insulin-resistant