Metabolism is essentially your body's engine — the entire process by which it burns calories. When we talk about raising your metabolism, we are talking about raising your metabolic rate — the rate at which you burn calories.

A higher metabolic rate burns more calories and makes it easier for you to lose weight, avoid weight gain, and maintain weight loss.

Your metabolic rate takes into account a number of factors, including:

• Resting metabolic rate (RMR): Your RMR is the minimum metabolic rate you need to stay alive and function while sleeping or at rest. About 50 to 75 percent of your total calories each day go toward your RMR.

• Thermic effect of exercise (TEE): TEE refers to the number of calories burned while exercising, whether aerobic or strength training.

Your metabolic rate also reflects:

• Thermic effect of food (TEF): Calories burned as your body digests food. About 10 percent of your metabolic effort goes toward TEF. Different foods have different thermic effects on metabolic rate:

• Protein increases it by 15 to 30 percent
• Carbohydrates increase it by 5 to 10 percent
• Fats increase it by 0 to 3 percent

• Non-exercise activity thermogenesis (NEAT): Calories burned during activities other than exercise, such as standing or walking

There are several factors that can slow your metabolism, including:

• Hypothyroidism
• Genetics
• Advancing age
• Lack of activity
• Loss of muscle mass

Some of these factors can't be changed, but as a thyroid patient, there are many things you can do to help raise your metabolic rate.

An important first step is to ensure that your hypothyroidism treatment is optimal. This means that rather than test levels that fall within the reference range, your levels are safely resolving your symptoms — including a slowed metabolism — as best as possible. For most patients, this means a TSH level below 2.0, and a Free T4 and Free T3 level in the top half of the reference range.

The timing of your meals plays a role in metabolism. Experts recommend that you eat breakfast — and make sure it includes protein. When you don't eat breakfast, your metabolism can drop, and fat-burning slows.

You should also focus on eating the bulk of your calories at lunch and make dinner your lightest meal. It's also helpful to avoid eating after 8 p.m. This allows your body to digest, process, and burn off energy in the break between your last meal and breakfast.

Very low-calorie diets can sabotage weight loss efforts by dramatically lowering the RMR. Some experts recommend that you avoid slowing the metabolism by eating enough calories for your RMR. My Fitness Pal has an online RMR calculator. Keep in mind that hypothyroidism and yoyo dieting often make your RMR significantly lower than the standard calculations. The Dexa RMR Test can provide a more accurate, personalized calculation of your RMR.

There are four reasons to include more protein in your diet:

• Protein helps you build and maintain muscle.
• Digesting protein burns more calories than digesting fat or carbohydrates.
• Protein increases post-meal calorie burn by up to 35 percent.
• Protein is filling, curbs hunger, and reduces calorie intake. One small study reported that a diet that is 30 percent protein results in 400 fewer calories eaten per day.

The Daily Reference Intake (DRI) for protein is 0.8 grams of protein for every kilogram of body weight.

Make sure you get enough fiber — experts recommend you get at least 25 grams each day. It can rev your metabolism and the fat burning process — in some cases by as much as 30 percent. Research also shows that a higher-fiber diet is associated with less weight gain. Focus on incorporating high-fiber foods into your diet. If you can’t get enough fiber from food, here’s a trick: Carry psyllium capsules and take them with each meal. You’ll get a high-fiber benefit from all the food you eat.

In his book The Toxin Solution, naturopath Joseph Pizzorno, N.D., has shown the clear link between exposure to various toxins and the risk of slowed metabolism, weight gain, and type 2 diabetes. To minimize the metabolic impact of exposure to toxins such as pesticides and hormones, choose organic fruits, vegetables, and dairy products, avoid hormones in meat and dairy products, and consider filtering toxins from your water.

Chemical components of spicy foods are known metabolism boosters. Capsaicin (the chemical that gives hot sauce and chili peppers their heat), as well as dihydrocapsiate (DCT), found in hot peppers, all can boost your metabolism.

To burn energy, your body needs adequate water. One study in The Journal of Clinical Endocrinology and Metabolism reported that metabolic rates increased 30 percent for an hour after drinking just two glasses of water. Drinking cold water burns more energy, and increases RMR by 50 calories a day. Also consider drinking before you eat. One study found that overweight adults who drank 16 ounces of water before meals lost 44 percent more weight.

Alcohol slows your fat-burning abilities because alcohol is burned off as fuel. Some research suggests that alcoholic drinks can decrease your fat-burning by up to 73 percent. If you are going to have a drink, choose lower-calorie options like wine or vodka, use low-calorie mixers, and keep it to one or two drinks.

To support fat-burning, energy, and metabolism, you need to get enough of several key nutrients. These include:

• B vitamins, especially B-12, and B-1 (also known as thiamine)
• Iron
• Vitamin D

Your health care provider can test your levels of these nutrients and recommend supplementation if necessary.

To evaluate iron levels, have ferritin - the stored form of iron - checked. If you supplement with iron, take it at least three to four hours apart from any thyroid medication.

A morning coffee may be able to promote fat-burning and increase your metabolism for the day by as much as 10 percent.

According to a study in the journal Physiology & Behavior, the average metabolic rate of people who drank regular coffee was 16 percent higher than decaf drinkers.

Just make sure you bypass high-calorie sweeteners and add-ins, like sugary syrups.

Coffee is not the only metabolism-boosting drink around. You can get as much — or even more — fat-burning and metabolic benefits from a variety of other drinks, including:

• Black tea
• Green tea
• Kola nut tea
• Yerba maté
• Matcha
• Oolong tea
• Goji tea

Aerobic exercise helps you consume oxygen and increases your metabolism and calorie-burning ability for hours after you finish your workout, due to excess post-exercise oxygen consumption, or EPOC.

For the metabolic benefits, aim for 30 minutes of some form or aerobic exercise several times a week.

For even more metabolic benefit, incorporate high-intensity interval training into your favorite aerobic exercise, like running, biking, or walking. Intervals are an effective way to burn more fat and increase your metabolism. For example, to add intervals, add short 30-60 second bursts where you go as fast as you can, and then return to normal speed for a minute to a minute-and-a-half for recovery. A good interval workout has at least 6 to 10 intervals.

Muscle is leaner and burns more calories than fat, so the more muscle you have, the higher your metabolic rate. According to some experts, strength training two to three times a week for 30 minutes can reverse at least 50 percent of metabolic slowdown and increase your resting metabolism by 100 calories a day.

Some forms of strength and resistance training include:

• Hand weights
• Free weights
• Resistance machines
• Resistance bands
• Pilates
• T-Tapp

"NEAT" stands for non-exercise activity thermogenesis — the calories burned off with non-exercise activities such as standing instead of sitting, walking up stairs, stretching, even tapping your fingers.

Activate your own NEAT and raise your metabolism by walking while talking on the phone, using a standing desk, or standing frequently while working. Standing burns 50 more calories per hour than sitting. Standing just three hours a day burns 30,000 extra calories — 8 pounds — in a year.

You may not be getting enough to help your metabolism. Research shows that "short sleep" — identified as less than seven hours per night — results in:

• Increase of visceral and belly fat
• Loss of muscle
• Lowered metabolic rate
• Increased appetite
• Increased cortisol, which stores fat
• Impaired glucose tolerance
• Increased risk of obesity

For the best metabolic boost, aim for seven to nine hours of sleep per night.

Our last metabolism-boosting tip may be the easiest of all: Just breathe! When you breathe, you consume more oxygen and stoke metabolism. One study found that a particular technique of yoga breathing — right-nostril breathing — can dramatically raise oxygen consumption and metabolism. In the study, four daily cycles of 27 right-nostril breaths increased oxygen consumption by a whopping 37 percent! Yoga Journal has advice on how to do right-nostril breathing.