4 Sneaky Things Affecting Your Metabolism, Per Dietitians

When you’re feeling sluggish or struggling to maintain your weight, it’s tempting to blame a “slow” metabolism. But metabolism isn’t a simple on-off switch you can flip with a new workout or diet trend. While what you eat and how much you move are important, your metabolism is far more nuanced. It’s actually a complex system—the sum of all the chemical reactions in your body that convert food into energy to power everything from your heartbeat to your thoughts to your daily movement.

While genetics, age and diet do influence how efficiently your metabolism works, many everyday habits also play a role. According to dietitians, these often-overlooked factors can impact how your body burns energy. The good news? Small, sustainable shifts may help support a healthy metabolism over time.

1. Your Stress Levels

Stress isn’t just a mood disruptor—it can also have a big impact on your metabolism. When stress becomes chronic, your body produces elevated levels of the hormone cortisol. In short bursts, cortisol helps your body respond to immediate challenges (“fight or flight” situations). But over time, it can contribute to imbalances that affect how your body uses and stores energy.

“When cortisol stays high, your body holds onto energy instead of burning it,” explains Katie Schimmelpfenning, RD.

Cortisol also influences your blood sugar by increasing glucose production in the liver and reducing insulin secretion. This makes your body more likely to store fat and less efficient at using energy. Activities like deep breathing, meditation, spending time in nature or regular movement can help calm the nervous system and support metabolic health.

2. Your Sleep Quality

A good night’s sleep is not a luxury; it’s a biological necessity for a well-functioning metabolism. It plays a vital role in metabolic health. Poor or inconsistent sleep can disrupt hunger and fullness hormones (ghrelin and leptin), making it harder to manage appetite and energy use.

“Your body’s circadian rhythm depends on adequate sleep,” shares Lisa Andrews, M.Ed., RD, LD. “Lack of sleep may slow down your metabolism and release hormones like cortisol, which impact blood sugar management and weight.”

Aim for 7 to 9 hours of high-quality sleep each night to help your metabolism stay healthy.

3. Your Gut Health

The trillions of microorganisms living in your digestive tract, known as the gut microbiome, play a critical role in your overall health, including your metabolism. These microbes help your body break down food, absorb nutrients and even produce essential vitamins.

“The microbes you have in your gut play a big role in your overall metabolism,” shares Taylor Berggren, M.S., RDN. An imbalance in gut bacteria can hinder your body’s ability to process nutrients efficiently. 

“Some important strains, called keystones, have been shown to be associated with lower rates of metabolic disease and diabetes, and introducing live probiotic strains can even improve markers of an imbalanced metabolism like A1C and post-meal blood glucose spikes in those with diabetes,” explains Berggren.

A diverse, fiber-rich diet that includes fruits, vegetables, whole grains and fermented foods can help nourish a healthy gut microbiome.

4. Your Insulin Sensitivity

Insulin is a hormone that helps your cells use glucose from your bloodstream for energy. But when your cells become less responsive to insulin, a condition known as insulin resistance, it may throw your metabolism out of balance.

“When our cells don’t respond well to insulin, the body has a harder time using glucose efficiently, and fat metabolism slows down. This makes it easier to store fat and harder to burn it,” explains Johannah Katz, M.A., RD. “Addressing insulin sensitivity through diet, movement, and lifestyle can be just as important as building muscle when it comes to supporting a healthy metabolism.”

A balanced diet, regular exercise and maintaining a healthy weight are key strategies for improving insulin sensitivity.

Dietitian-Recommended Ways to Support a Healthy Metabolism

While you can’t control factors your genetics or stop the clock, you can adopt habits that support your body‘s metabolism. Here are some actionable tips that are more well-known and equally as important to prioritize:

• Prioritize Protein: Including an adequate amount of protein with every meal and snack is a powerful way to support your metabolism. Your body uses energy to digest and process food, a phenomenon known as the Thermic Effect of Food (TEF). “Protein increases TEF the most, so you burn more calories when you eat protein compared to carbs and fat,” explains Marita Radloff, M.S., RDN, LD. “Aim for at least 20-30 grams of protein at meals and 10-15 grams of protein for snacks to support your metabolism and stay full.”
• Build More Muscle: Strength training helps preserve lean muscle mass, which burns more calories at rest than fat tissue. Incorporating resistance training—such as lifting weights or using resistance bands—even just two times per week, can support a more active metabolism over time.
• Eat Regular Meals and Snacks: Skipping meals can affect your metabolism and how your body regulates blood sugar. One study found that skipping lunch for two days in a row led to a higher blood sugar spike after dinner compared to days when lunch was eaten. Interestingly, skipping breakfast or dinner didn’t have the same effect on blood sugar at the next meal. While occasional meal shifts happen, eating regular meals and snacks can help maintain consistent energy and metabolic balance.

Our Expert Take

Metabolism is a complex and highly individual process influenced by much more than just food and exercise. While fueling your body well and moving regularly are foundational, supporting your sleep, managing stress and prioritizing gut health are equally important.

Instead of chasing a quick fix, consider small daily choices that help your body function at its best. These sustainable habits can add up to long-term benefits for your energy, well-being and metabolic health.