You’re hitting the gym on the reg, and you’re nailing your macros. You’re drinking enough water and getting in bed at a reasonable time…

...But the scale isn’t budging. 

Sound familiar? Stress does affect weight loss, and if you feel like you’re doing everything right, but you aren't seeing the results you want, stress may be the culprit.


does stress affect weight loss? Working Against Gravity Nutrition


What is "Stress"?

“Stress” describes experiences that are either emotionally or psychologically challenging [1]. Stressors can be acute or chronic and can vary in magnitude. Acute stressors are the everyday hassles -- like not being able to find toilet paper during a pandemic or getting to work late after being stuck in traffic. 

You may experience chronic stress after losing a loved one or living through a natural disaster. This more extreme stress response is generally marked by a prolonged feeling of being overwhelmed or pressured. Both acute and chronic stress impact cognitive function by way of the prefrontal cortex [1], and bodily function through altered levels of cortisol [2]. Disruption in each system can slow or completely stall your progress in weight loss or muscle gain.

Your Brain on Stress: A Helpful Example

Since the brain is your body’s “central control”, let’s start here! 

Let's say you set the general goal to “eat healthier” when they start any kind of nutrition and lifestyle change. To achieve this goal, you make a plan to eat out less. Things go great for the first few days, but then your boss gives you an impossible deadline which instantly puts you in a state of stress.

Instead of eating your meal-prepped lunch, you opt to go to Five Guys with your coworker. Then you are mad at yourself for straying from your goal and stress out even MORE! Does this sound familiar?

If so, know that there is a perfectly good explanation for your decision; in fact, it was not a decision at all. When you are under stress, the decision-making part of your brain is compromised [3].

The prefrontal cortex is located in the front region of the brain and is responsible for regulating thoughts and actions, which includes selecting and coordinating goal-directed behavior. This region of the brain is highly sensitive to stress. When you are stressed, your brain reallocates resources so it can focus on the stress and, in doing so, resorts to autopilot and routine to save energy. 

This happens at the expense of conscious decision-making – like choosing to skip the burger. When the brain is directing its attention to stress, it shifts to making less outcome-controlled behavior, or goal-directed behavior, and relies on what is easy and familiar [3].

The brain does not discriminate; it relies on all habits, whether they are healthful or not.



How Stress Affects Weight Loss

Stress also impacts your hormones, specifically cortisol. 

Cortisol is your body’s primary stress hormone. When you experience stress, the adrenal cortex releases cortisol which prompts an increase in heart rate and in energy level so your body remains on high alert [3]. 

When you face continuous stressors, your body thinks it is fighting for survival all the time, and so your cortisol level is at a constant high. Research has shown that there is a link between increased cortisol and weight gain [4]. Higher baseline cortisol levels predict short-term weight gain over a 6-month period [5]. High levels of cortisol affect your weight loss through increased appetite, food choices and even changes the way your body stores fat.

Let’s break these impacts down a bit more...

  1. Increased appetite: Cortisol stimulates appetite. It speeds up the metabolism of macronutrients because your brain thinks it needs more fuel to fight whatever stressor it is facing.

  2. Food choices: Cortisol influences food selection and consumption. Cortisol makes you crave highly palatable foods (foods high in fat or sugar). This occurs because fats and sugar release dopamine, which can make you temporarily feel better, counteracting the negative feelings associated with stress.

  3. Fat stores: When cortisol is high, your energy is high (from the stress). The body needs an outlet for this energy. Unfortunately, most of the time, you are stressed, and you are not in a position to take a quick run or hit a set of pushups. Instead, your body instinctively tries to calm itself down by releasing insulin. Cortisol then turns this energy-storing insulin into fat. So, even if you are eating healthy, you still do not stand a chance against cortisol. No matter what you eat, when you are in a stressed state, your body turns the nutrients into fat.

Exercising may seem like an easy fix to release all that built-up energy from stress, right?

This actually isn’t the case! Here’s why...

Stress and Muscle Gain

Exercise causes stress on the body and central nervous system. Adding exercise to your already stressed state can do more harm than good, especially if your goal is to gain muscle. 

Remember cortisol? Unfortunately, it affects weight loss AND muscle gain. Here’s how:

  1. Prolonged recovery: Higher cortisol levels cause persistent muscle tension, the buildup of lactic acid, and decreased blood flow [6]. All of these factors impact the elasticity of your muscles. Training while stressed is often less fruitful because the range of motion and movement patterns change. During exercise, your muscle fibers endure tiny tears. During recovery, your body repairs these tears, making the muscle stronger than before. When you are stressed, muscles take longer to repair themselves.
  2. Threatened immunity: When you are stressed, certain body systems, including the immune system, shut down so your body can focus on the stressor. High levels of cortisol signal the body to release fewer white blood cells. White blood cells play an important role in immunity. When your white blood cell count is low, you are more likely to get sick and stay sick, costing you valuable training time in the gym.

  3. Inhibited protein synthesis: Your muscle cells are in a constant state of building and breaking down. Muscle growth occurs when the building (protein synthesis) exceeds the breaking down (protein degradation). When cortisol is present, muscle cells increase protein degradation [2]. This means protein degradation happens at a faster rate than protein synthesis, which prevents muscle growth.

How to Keep Stress From Ruining Your Progress

Okay, okay, you get it! Stress plays a huge role in your ability to lose fat and/or gain muscle. The next question (and the reason you’re probably here!) is, “What can I do about it?”

Since the brain can’t self-regulate when you’re stressed, and cortisol levels are running high, establishing goal-supporting habits, adding stress-relieving activities, and creating cortisol-reducing strategies ahead of time is critical to your success. 

In a perfect world, you would be able to eliminate ALL stress from your life, but let’s be honest; stress is unavoidable these days. So why not build some armor to protect yourself and your goals when stress creeps into your life?

The trick is to retrain your brain and create go-to routines that support your goals instead of working against them. That way, when your brain goes into autopilot, you still make progress.

Habits save you from having to make in-the-moment decisions which we know tend to do the opposite of supporting our goals. Here are some habits you can work on:

  1. Sleep: Sleep helps your body balance cortisol levels. Be mindful of daily caffeine intake to help achieve a more natural sleep cycle and check out this article for more sleep-improving tips.

  2. Exercise: Overtraining can cause more stress to the body! So, a go-to workout alternative to your normal routine can be a huge help when stress is higher. Take a long walk instead of your usual weight training, or replace your long-distance run with a yoga class. Whatever you choose, it should be less strenuous than your usual go-to. If you’re still convinced keeping it low-key will stall weight loss, check out this article.

  3. Diet: Heightened cortisol levels can reduce immunity, so it is crucial to eat foods rich in vitamins. This gives you the best shot at remaining in good health despite having a low white blood cell count. A 1:1 coach can help you dial in your nutrition choices based on your schedule, needs, and preferences.


Ultimately, your brain does not have the energy to create and practice habits when you are already in a stressed state. This means that establishing goal-supporting habits when your brain has the capacity and willpower to make decisions is key. 

Next time you feel stressed and behave in a way that does not support your goal, remember that there is an explanation, you’re human, and now you have the tools to regain control.


  1. McEwen, B.S. (2007). Physiology and neurobiology of stress and adaptation: central role of the brain. Physiology Review, 87(3):873-904. 10.1152/physrev.00041.2006.
  2. Thau, L., Gandhi, J., & Sharma, S. (2021). Physiology, cortisol. StatPearls Publishing.
  3. Quaedflieg, C., Stoffregen, H., Sebalo, I., & Smeets, T. (2019). Stress-induced impairment in goal-directed instrumental behaviour is moderated by baseline working memory. Neurobiology of Learning and Memory, 158: 42–49.
  4. Roberts, C., Campbell, I., & Troop, N. (2014). Increases in weight during chronic stress are partially associated with a switch in food choice towards increased carbohydrate and saturated fat intake: Stress food choice weight increase. European Eating Disorders Review, 22(1), 77–82.
  5. Chao, A., Jastreboff, A., White, M., Grilo, C., & Sinha, R. (2017). Stress, cortisol, and other appetite-related hormones: Prospective prediction of 6-month changes in food cravings and weight: Stress, Cravings, and Weight. Obesity, 25(4), 713–720.
  6. American Psychology Association. (2018, November 18). Stress effects on the body.