In this article
In an American Psychological Association survey, 37 percent of adults said stress had left them feeling tired or fatigued in the past month. Another 39 percent reported low interest, motivation or energy.
Stress fatigue is one of the most common ways stress shows up in the body. This article explains what links stress and fatigue, why the popular idea of adrenal fatigue doesn’t hold up, and where fiber can help break the cycle.
By the numbers
- 37% of adults said stress left them tired or fatigued in the past month
- 39% reported low interest, motivation or energy from stress
- 4 weeks of a fiber and fermented food diet lowered perceived stress in a small trial
The stress fatigue loop
Stress and fatigue feed each other. A demanding stretch drains your energy, and being tired makes everyday pressures feel heavier.
The same survey found that 72 percent of adults reported at least one physical symptom of stress in the past month. Tiredness was one of the most common, alongside upset stomach and indigestion.
That digestive link is worth noticing. It hints at how closely stress, the gut and energy are tied together.
Several everyday habits tend to change under stress, and many of them make tiredness worse.
- Comfort eating: sweet and refined snacks become more tempting
- Poorer sleep: racing thoughts and late nights cut into rest
- Skipped meals: busy days lead to long gaps and then large meals
- Less movement: exercise is often the first thing to go
Fiber can’t remove the source of stress. But it can soften several of these links, especially the ones involving food, sleep and the gut.
It also helps to see the loop as something you can interrupt at more than one point. Changing what’s in your snack drawer is often easier than changing your workload.
Viscous soluble fiber and fermentable prebiotic fiber are the types most tied to stress fatigue, through steadier blood sugar and support for gut health.
Cortisol and the adrenal fatigue myth
When you’re under stress, your adrenal glands release cortisol, a hormone that helps mobilize energy and manage the response. That’s normal and useful in the short term.
Many websites claim that long term stress wears out the adrenal glands, causing adrenal fatigue. Endocrinologists disagree.
The Endocrine Society states that adrenal fatigue is not a real medical condition. In a 2018 report in Endocrine Today, endocrinologist Theodore Friedman put it simply: “When you’re under stress, the adrenals make more cortisol, not less.”
Put plainly, the glands respond to stress by working harder, not by running out. Fatigue during stressful times is real, but it has other explanations.
A 2016 systematic review of 58 studies found conflicting results and poor quality evidence for the idea. It noted that people with chronic fatigue syndrome tend to have a normal cortisol profile.
Why the label matters
Calling stress fatigue “adrenal fatigue” can lead people toward unproven supplements and tests. It can also distract from real, treatable causes of tiredness.
Ongoing exhaustion can come from poor sleep, depression or anxiety, thyroid problems, anemia and many other conditions. These are worth ruling out if fatigue doesn’t lift when stress eases.
The more useful question is usually what stress is doing to your daily habits. That’s where diet, sleep and movement come in, and where small changes can make a noticeable difference.
Comfort food, blood sugar and energy
Reaching for something sweet is one of the most common responses to stress. The link between blood sugar and energy suggests it may make fatigue worse.
A 2019 review of 31 studies in Neuroscience and Biobehavioral Reviews found that carbohydrates, mostly sugars, left people more tired and less alert within the first hour. There was no lift in mood to make up for it.
That makes the classic stress snack a poor trade. It offers a moment of comfort, followed by the very tiredness you were trying to escape.
Stress can also make people skip meals and then overeat later. A large, fast digesting meal after a long gap is a recipe for the rise and fall that leaves you sluggish in the afternoon.
Regular meals that include fiber, protein and some healthy fat help keep that pattern from forming.
Comfort foods with more staying power
- Warm oatmeal with sliced pear and a spoon of nut butter
- Whole grain toast with hummus or mashed avocado
- Plain yogurt or kefir with berries and a sprinkle of chia
- A small handful of nuts with an apple
These still feel satisfying, but the fiber slows digestion, so you’re less likely to crash an hour later.
Curious how much fiber your go-to snacks and meals actually contain? Our fiber calculator totals it up in seconds.
Stress, sleep and what you eat
Stress often shows up at night first. Lying awake or waking often leaves you running on empty the next day, which makes stress harder to handle.
Diet appears to play a part in sleep quality. A 2016 study of 26 adults in the Journal of Clinical Sleep Medicine found that eating more fiber was linked to more time in deep, slow wave sleep, while more sugar was linked to more arousals from sleep.
The study was small and showed links rather than proof. Still, it’s a reason to keep evening meals fiber rich and to go easy on sugary late night snacks during stressful periods.
Other sleep habits matter too. A consistent bedtime, a short wind down without screens and some daylight earlier in the day all support better rest alongside a better diet.
Gut health and stress
The gut and brain are in constant communication, and stress can affect digestion just as digestion can affect mood. Gut health and stress are closely tied.
A 2022 trial from APC Microbiome Ireland tested whether diet could change how stressed people felt. Researchers asked 45 healthy adults with fairly low fiber diets to follow either a psychobiotic diet or general healthy eating advice for four weeks.
- Prebiotic fruits and vegetables: 6 to 8 servings a day, such as onions, leeks, cabbage, apples and bananas
- Whole grains: 5 to 8 servings a day
- Legumes: 3 to 4 servings a week
- Fermented foods: 2 to 3 servings a day, such as kefir and sauerkraut
People on the psychobiotic diet reported lower perceived stress than the control group, and those who stuck to it most closely saw the biggest drop. Sleep improved in both groups.
The trial was small and short, and diet tracking relied on self report. But it suggests that fiber and stress are connected in a way you can act on through everyday food.
The study also didn’t measure fatigue directly. Because stress is such a common driver of tiredness, lowering perceived stress is a reasonable route to feeling less drained.
Want a structured plan for building gut friendly habits? Our gut guides walk you through it one week at a time.
Using fiber to ease stress fatigue
When stress is high, simple routines are easier to keep than ambitious plans. These habits target the food, sleep and gut parts of the loop.
- Keep a fiber rich breakfast so the day doesn’t start with a sugar spike
- Plan a stress snack that pairs fiber with protein
- Avoid long gaps between meals on busy days
- Eat a variety of plant foods to feed a wider range of gut microbes
- Add a fermented food such as yogurt or kefir most days
- Keep evening meals lighter on sugar to protect sleep
These foods make easy building blocks, with values from the Dietary Guidelines for Americans.
| Food | Serving | Fiber (g) | Why it helps |
|---|---|---|---|
| Lentils, cooked | 1/2 cup | 7.8 | Slow release carbs and prebiotic fiber |
| Raspberries | 1 cup | 8.0 | A sweet option with plenty of fiber |
| Pear | 1 medium | 5.5 | Portable snack for busy days |
| Apple | 1 medium | 4.8 | Pairs well with nuts |
| Oat bran, cooked | 1/2 cup | 2.9 | Warm, viscous fiber breakfast |
| Almonds | 1 oz | 3.5 | Fiber with protein and fat |
A low effort day for stressful weeks
- Breakfast: overnight oats made the night before with chia, berries and yogurt
- Lunch: a can of lentil soup topped with spinach, with whole grain bread
- Snack: a pear and a small handful of almonds kept at your desk
- Dinner: a bean and vegetable stir fry over brown rice, with kefir on the side
None of these take much time or decision making, which matters when your mental energy is already stretched. Preparing one or two items ahead on a calmer day makes the whole week easier.
The goal isn’t a perfect diet during a hard week. It’s removing the easiest routes to a sugar crash and keeping your gut well fed while the pressure is on.
Looking for simple meals for stressful weeks? Our recipe eBooks have plenty of quick ideas.
How long before you notice a difference?
- Same day: fewer sugar crashes once snacks and meals include fiber
- 1 to 2 weeks: steadier routines and better evening meals may support sleep
- About 4 weeks: the stress trial saw changes over this span
Increase fiber gradually, about 5 grams a week, and drink more water. A sudden jump can cause bloating, which won’t help when you’re already stressed.
If fatigue continues even after stress eases, or comes with other symptoms, it’s worth looking for another cause.
Stress fatigue: common questions
Can stress make you physically tired?
Yes. In an American Psychological Association survey, 37 percent of adults said stress left them tired or fatigued in the past month.
Is adrenal fatigue real?
No. The Endocrine Society says adrenal fatigue is not a real medical condition, and under stress the adrenal glands make more cortisol, not less.
Can fiber lower cortisol?
The evidence is limited and mixed. Fiber’s clearer benefits for stress fatigue come from steadier blood sugar, better sleep quality and gut support.
What should I eat when stressed and tired?
Choose foods that pair fiber with protein, such as oatmeal with nut butter or an apple with almonds. These digest slowly and avoid a sugar crash.
Does gut health affect stress?
Research suggests it can. A small four week trial found a diet rich in prebiotic fiber and fermented foods lowered perceived stress.
How much fiber helps with stress?
Studies haven’t set an amount for stress, and needs vary by person. Our fiber calculator shows the target that fits you.
Why does sugar make stress fatigue worse?
A review of 31 studies found sugars left people more tired and less alert within an hour, with no mood boost to make up for it.
Sources
- American Psychological Association. “Stress in America 2013: Snapshot.” 2013. https://www.apa.org/news/press/releases/stress/2013/snapshot
- Healio Endocrine Today. “In age of internet diagnoses, endocrinologists confront myth of ‘adrenal fatigue’.” 2018. https://www.healio.com/news/endocrinology/20180410/in-age-of-internet-diagnoses-endocrinologists-confront-myth-of-adrenal-fatigue
- Mantantzis K, et al. “Sugar rush or sugar crash? A meta-analysis of carbohydrate effects on mood.” Neuroscience and Biobehavioral Reviews. 2019. https://eprints.lancs.ac.uk/id/eprint/134426
- St-Onge MP, et al. “Fiber and saturated fat are associated with sleep arousals and slow wave sleep,” via American Academy of Sleep Medicine release. Journal of Clinical Sleep Medicine. 2016. https://www.sciencedaily.com/releases/2016/01/160114213443.htm
- APC Microbiome Ireland, University College Cork. “Food for thought: feeding microbes to deal with stress.” Berding K, et al. study in Molecular Psychiatry. 2022. https://www.ucc.ie/en/apc/news/apc-news/food-for-thought-feeding-microbes-to-deal-with-stress.html
- U.S. Department of Agriculture and HHS. “Food Sources of Dietary Fiber.” Dietary Guidelines for Americans 2020 to 2025. https://www.dietaryguidelines.gov/resources/2020-2025-dietary-guidelines-online-materials/food-sources-select-nutrients/food-0
