What Is the Difference Between Slow & Fast Metabolism?

The metabolism gets blamed for weight issues on both ends of the spectrum. If it's too slow, you may battle to lose weight; if it's too fast, you may struggle with gaining. Whether it's slow or fast, tweaking your diet and exercise habits may help you manage your metabolic rate. If you're concerned that your slow or fast metabolism may be a medical issue, consult your doctor to discuss possible causes and solutions.

Metabolism refers to the chemical processes responsible for maintaining basic body functions such as breathing, cell building and digestion. These chemical reactions require energy, which comes from calories in food. Your metabolic rate is the number of calories you need each day to maintain these basic body functions.

The difference between slow and fast metabolism is how many calories you burn to support these functions. A slow metabolism burns fewer calories than a fast one. Factors that determine your metabolic rate include gender, body composition, age, daily activity and genetics.

The basal metabolic rate, thermic effect of food and activity are the three parts that make up your metabolic rate. The BMR is the number of calories you burn to maintain the parts of your body you don't think about, such as your heart beating, lungs breathing and maintenance of your muscle mass. The BMR burns 40 to 70 percent of your daily calorie needs.

If your metabolism is slow, it's because your BMR is slow. Every 100 calories you eat requires 10 calories of energy to digest, which is referred to as the thermic effect of food. Your physical activity also burns calories and includes the energy needed to get you out of bed in the morning and power your 5-mile run.

If you're putting on weight while eating the same kinds of food you've eaten for decades, your metabolism may be slowing down. Muscle burns more calories than fat tissue, but as you get older, you may be less active and your calorie-burning muscle turns into fat, leading to the metabolic slowdown. This is also one reason why women generally have slower metabolisms than men — genetically they have less muscle. Eating too few calories can also cause a drop in your metabolic rate.

Read more: How to Increase Metabolism for Seniors

If you're blessed with a fast metabolism, your friends may tell you how jealous they are that you can eat whatever you want and not gain weight. Genetics may be the major player in your fast metabolism. If you're a muscular man, you may have an innate higher metabolism, but your higher calorie burning may also be due to hard work. Working out and building muscle pay off when it comes to your metabolic rate, which is why athletes and bodybuilders get to eat large quantities of food.

Read more: How to Gain Muscle With a Fast Metabolism

If you're cutting calories to lose weight, don't go too low. Dipping below 1,200 calories for women and 1,800 calories for men may cause your metabolism to stall, essentially creating a slow metabolism. Bring the calories back up to increase your calorie-burning power.

Adding muscle to your frame might give your slow metabolism a boost. Strength-train twice a week using free weights or body-resistance exercises such as squats, lunches and push-ups, to build calorie-burning muscle.

Getting more cardio is another way to jump-start your metabolic rate. Also, find more ways to be active. Up your daily walk from 30 to 60 minutes. Take a walk around the office every hour. Pace when you're on the phone. Stand at a counter to type your emails and letters.

Read more: The One Food Scientifically Proven to Boost Metabolism

If you're having a difficult time gaining weight or can't stop losing due to your fast metabolism, you need to eat more calories. These extra calories should come from nutritious foods to promote overall good health and weight gain. For extra calories, eat whole-grain bagels and dense whole-grain bread; cheese and whole milk; eggs, fatty fish and beans; avocados and 100-percent fruit juice; peas and potatoes and nuts, seeds and oils.

Add high-calorie snacks such as 1/4 cup of dry-roasted mixed nuts for 200 calories or 1/4 cup of hummus with a 6-inch whole-wheat pita for 260 calories. A high-calorie nutrient-rich smoothie such as a 6-ounce container of yogurt blended with a medium banana, 1 cup of sliced strawberries and 2 tablespoons of almond butter for 480 calories can up your calorie intake.