5 Ways to Slow Down Your Metabolism

Kinsey Mahaffey
Kinsey Mahaffey
| Stay Updated with NASM!

For someone who wants to gain weight and/or increase muscle mass, having a fast metabolism can be seen as a roadblock when it comes to achieving those goals. Maybe you’ve tried eating more to pack on the muscle, but you just seem to burn through all the calories that you consume without gaining a pound.

You might be wondering if there’s some way to slow down your metabolism to reach your goals. This article will discuss what it takes to slow down the metabolism and some tips for gaining weight the healthy way.

Note: Before making any drastic changes to gain weight, it’s important to check with your physician/registered dietician to make sure that you follow the plan that’s right for you. Also consult a nutrition coach for additional insight. 

An Overview of Metabolic Rate

In the scope of health and fitness, we use metabolic rate to describe the rate at which a person burns calories in their body. Some people have a high (or fast) metabolic rate, while others have a low (or slow) metabolic rate. Several factors can influence our metabolic rate, including:

Age – metabolism often slows as we age due to sarcopenia, an involuntary loss of muscle related to aging.

Gender – Men tend to have faster metabolisms than women.

Muscle mass – More muscle mass means a faster metabolism.

Body size – The more you weigh, the faster your metabolism will typically be.

Physical activity – Increasing physical activity can also increase your metabolism.

Hormones – Hormone disorders can either speed up or slow down the metabolism, depending on the disorder. Hyperthyroidism speeds it up, while Cushing’s syndrome slows it down, for example.

What we eat and what we do can also affect our metabolic rate:

Thermic Effect of Food (TEF): This is the energy used to digest a meal and convert it into energy. Simple carbohydrates and fats have a lower thermic effect than protein. Metabolic rates will rise as the TEF rises.

Thermic Effect of Activity (TEA): Activity level directly corresponds with how many calories we burn each day. Simply put: you burn more calories when you’re more physically active and your metabolism is boosted.

Non-Exercise Activity Thermogenesis (NEAT): The energy that is expended performing activities not related to intentional exercise (such as walking from your car to work, fidgeting, sitting, standing, etc.). The more you move around throughout your waking hours, the more calories you will burn. Your metabolism is likely to be higher the neater you perform each day.

The way that your body responds to each of these factors is very individualized and changes may not result in an equivalent response in your metabolism. If you think that your metabolic rate might be the reason you haven’t been able to reach your health and fitness goals, it’s probably a good idea to confirm the issue and get to the root of it.

You can schedule an RMR (Resting Metabolic Rate) test at a fitness or medical facility in your area to look at your metabolic rate. This can cut out the guesswork when it comes to making a nutrition and fitness plan to reach your goals. If you do find that your metabolic rate is faster or slower than normal, it might be recommended to pursue further testing to rule out underlying hormonal issues as the cause.


Generally, a slower metabolism is associated with weight gain. For someone who has a fast metabolism, their issue may be that they have difficulty gaining weight. Why would someone want to gain weight? There are many possible reasons, but here are a few: to promote fertility, boost their immune system, boost self-confidence, or for other health reasons.

5 Ways to Slow Your Metabolism

Certain lifestyle changes can influence the speed of your metabolism. However, a fast metabolism that is caused by a hormone disorder may require medical treatment to regulate the issue.

For healthy individuals looking to slow down their metabolism: Consider the behaviors that speed up metabolism. We can reverse-engineer the process to discover what will slow it down.

1. Eat fewer calories: Eating less will reduce the TEF which can slow the metabolism. Over time, a slower metabolism may lead to weight gain.

2. Decrease NEAT: Less movement throughout the day will result in a slower metabolism since the body won’t need to produce extra energy to perform this extra movement.

3. Focus on low to moderate-intensity cardio and minimal strength training: Having muscle is important for health but gaining muscle will speed up the metabolism. One technique for slowing the metabolism while also staying physically fit is to find the balance of muscle strengthening exercises and low to moderate-intensity cardio that keeps you fit but avoids gaining excess muscle mass.

This might look like walking 30 minutes a day and performing full-body strength training 2x/week in the stabilization endurance or strength endurance phases (Phases 1 or 2) of the OPT Model.

4. Eat less frequently: Eating more meals per day revs up the metabolism while eating meals that are spaced out can slow the metabolism.

5. Modify your macros: Eat meals that are higher in simple carbohydrates, lower in protein, and moderate in healthy fats for a nutrient balance with a lower TEF. Read also - How to Count Macros.

Weight Gain Tips

If you want to gain weight because you are classified as underweight (a BMI below 18.5), you can adjust your activity levels as described above in #2 and #3 along with making some dietary changes:

Track your calories. You may find that you’re not eating as many calories as you think, and some simple swaps can boost your caloric intake without making you feel overly full.

Increase calorie intake. Eat 300 to 500 calories more per day than you currently eat to gain weight slowly.

Eat healthy, calorie-rich foods. You don’t need to cram a bunch of junk food to gain weight. Instead, try these healthier, calorie-dense options:

Protein: Red meat, chicken with skin, salmon or oily fish, higher fat dairy products (5% or full-fat Greek yogurt, as an example)

Carbohydrates: Potatoes, brown rice, whole grain products

Fats: Nuts, olives, avocado, salad dressings, and high-fat cheeses

Find the macro balance that works best for you and your goals!

These dietary changes can also help someone who has difficulty gaining weight but would like to bulk up in the gym. The main difference in the approach will be when it comes to physical activity. When bulking, the goal isn’t just to gain weight, it’s to build muscle.

To increase muscle mass, you’ll want to do strength training 3-4 days/week at 6-12 repetitions and 3-5 sets per exercise. Strength training can help you boost your hunger, which will help you to eat the food that will fuel your goals. You may also add in extra snacks as needed to boost caloric intake.

in Summary

A person’s metabolic rate can fluctuate due to genetics, physical characteristics, hormone health, nutrition, and physical activity. Knowing your metabolic rate can influence the nutrition and movement choices that you make to reach your goals.

Before trying to change the rate of your metabolism, it’s important to consider whether your metabolism is the culprit and if so, to find a healthy way to make changes.

The good news is that there are simple steps that you can take if you need to gain weight for health reasons or to meet your fitness goals. As mentioned previously, it’s always advised to contact your health care practitioner and/or registered dietician to find the plan that’s best for you!


Cleveland Clinic (2022). High Calorie Foods: Snack Ideas for Weight Gain. Cleveland Clinic,

Cleveland Clinic (2022). Hormonal Imbalance: Causes, Symptoms & Treatment. Cleveland Clinic,

Mullur, R., Liu, Y.-Y., & Brent, G. A. (2014). Thyroid Hormone Regulation of Metabolism. Physiological Reviews, 94(2), 355–382.

The Author

Kinsey Mahaffey

Kinsey Mahaffey

Kinsey Mahaffey, MPH, is a Houston-based fitness educator, personal trainer and health coach who developed her commitment to lifelong fitness while playing Division I volleyball. She’s passionate about helping others cultivate a healthy lifestyle and enjoys educating other fitness professionals who share this vision. She’s a Master Instructor and Master Trainer for NASM. You can follow her on LinkedIn here.


Start Your Fitness Career Today

Become A Top-Notch Certified Personal Trainer

A NASM advisor will contact you to help you get started.

Get Started