Because your thyroid is so powerful, it can be to blame for a number of issues. If you're always cold, it could be hypothyroidism — a condition where your thyroid doesn't produce enough of its hormones. Your metabolism slows down, and your body isn't able to get warmer. Other symptoms include hair loss, dry skin, and fatigue.

Thyroid problems affect more than 12 percent of Americans, and around 60 percent of people with some kind of thyroid disease don't even know they have it.

If your body overall feels warm enough but your hands and feet are cold, poor circulation could be the culprit. Proper circulation is what keeps your blood flowing to your extremities; if it's not functioning properly, you could turn into Icicle Feet. The underlying problem could be a number of things, including cardiovascular disease and smoking. A doctor will be able to help you pinpoint it.

Fats have gotten such a horrible reputation, and for all the wrong reasons. You need healthy fats in your diet — like avocado, nuts, and seeds. Fatty foods help your body maintain its core temperature. Have you ever noticed how in the winter, you're craving all your favorite hearty, fatty comfort foods? That's no coincidence.

A lack of body fat means you don't have that much needed insulation to keep you warm. Plus, if you're eating less to maintain that low body fat percentage, you're probably slowing your metabolism down; and as we know, a slow-moving metabolism means you might not be able to produce warmth. Added muscle will also help your body produce and maintain heat, and keep that metabolism hustling.

Aside from how water helps keep your metabolism moving (are you noticing a pattern here?), it also serves another important role. The water in your body traps heat and then slowly releases it over time, helping to keep you at a comfortable temperature. Consider that your body is mostly water. So, if you're dehydrated, it simply can't function at the level it really wants to.

You can get iron from foods like spinach, lentils, and broccoli; but if you're not getting enough of this important mineral in your nutrition, it could cause constant coldness. Iron helps your blood cells move oxygen through your body, which delivers heat and nutrients to your cells. Furthermore, an iron deficiency could contribute to hypothyroidism. You can supplement this mineral, but as you probably already know, getting it primarily from healthy foods is ideal.

Now we know that red blood cells are involved in helping to keep you at a stable temperature, and you need vitamin B12 to make red blood cells. If you don't get enough of it, the result could be low red blood cell count, and — you guessed it — being cold all the time. You can get B12 from eggs, milk products, meat, chicken, and fish. If you think you're eating enough of it and you're still cold, it's possible your body isn't absorbing all of it properly.

When we start digesting a meal we just ate, our bodies go through a process called diet-induced thermogenesis. This causes the body temperature to rise. Foods high in protein increase DIT more than foods that are starchy or fatty, so they help keep you warm. There are plenty of protein-rich foods that are delicious and nutritious. Look to yogurt, cheese, chicken, and fish for lots of protein.

Fatigue is the enemy, and it can wreak havoc on you mentally, physically, and emotionally. If you're not catching enough quality ZZZs, your hypothalamus could take a hit, and your hypothalamus controls the part of the brain that regulates temperature. Also — and not to sound like a broken record — but a lack of sleep could lead to a slower metabolism, which means poor circulation and less body heat.