This is the type of vitamin D that circulates in the blood. Itâs considered a good reflection of how much vitamin D youâve absorbed from sun exposure and taken in from foods. Levels of vitamin D are expressed in nanomoles/liter (nmol/L) or nanograms/milliliter (ng/mL). According to the Office of Dietary Supplements (ODS), the results can indicate the following:
Other Health Conditions. On rare occasions, being tired after a meal or simply sleepy all the time could be a sign of another health problem. Diabetes, anemia, underactive thyroid, celiac disease, food intolerance, and sleep apnea can make post-meal drowsiness worse.
Chronic Fatigue Cause No. 7: Food Allergies. While food is supposed to give us energy, some doctors believe hidden food intolerances -- or allergies -- can do the opposite. According to Rudy Rivera, MD, author of Your Hidden Food Allergies Are Making You Fat, even mild food intolerance can leave you feeling sleepy.