Been reading a lot about thyroid lately for energy metabolism. Try eating some thyroid raw, but more importantly avoid PUFA, poly unsaturated fatty acids, or anything other than beef, beef fat, dairy fat, coconut fat (such as oil), and saturated/monounsaturated fat in general. Any animal other than beef, venison, or red meat animals generally has enough PUFA to cause fatty acid oxidation in your body. Saturated fats dont typically do this, and neither do monounsaturated fatty acids. Pork and pig is the highest source of PUFA, with duck/chicken as close seconds. PUFA oxidation prevents glucose oxidation, and glucose oxidation is needed for proper thyroid function. Dont be afraid of carbs, and glucose, you need them for your thyroid. A sluggish thyroid will cause daytime drowsiness and could be your problem easy. Get off the low carb bandwagon if you are on it, and make sure you eat clean carbs from fruit and veggies.
Sure, you may not believe the philosophy of it all but neither did I until I got bloodwork and confirmed that this stuff does work. These are studied in science also, not just philosophies like many paleo promoters purport. We wouldnt have had access to many PUFA animals like ducks, pigs, and chickens anyway in my opinion. Most of the history shows us hunting large game from red meat animals. Besides red meat animals are also the only ones that nobody is allergic to. If you cheat on your diet, be careful of all processed food, which contains waaayyy too many PUFA like any corn, soy, or other processed oil.
I eat coconut oil because the medium chain triglycerides are pro thyroid. I buy mine from nutiva who never go over 104 degrees, so it is basically raw. Dont believe anyone that tells you that it is bad for you if over like 96 degrees. Sure, thats why in thailand, where most of the globes' coconut oil is produced is typically over the 100's in the warmer seasons. Its the same idiocy as saying dont eat an animal if you are stranded in the wilderness because the animal died and freezes on the ground so it is bad.