Metabolic Health
Stress, Sleep, and Snacking
When you've had a rough day and you go looking for a snack, you often aren't hungry. Stress doesn't make everyone eat more, but it does change what people reach for, and it makes it harder to sleep, which makes the next day's eating harder too. This article covers what stress changes, what cortisol has to do with belly fat, how sleep fits in, and two things to try before you eat.
When stress lasts for hours or days, the hormone cortisol stays up, and cortisol raises appetite, often for food with a lot of calories in it. In one study, healthy adults woke up hungrier after their cortisol was raised overnight. The pull toward a snack on a hard day doesn't mean your body needs food.
It doesn't make everyone eat more. In a survey of 212 students, 42 percent said they eat less under stress and 38 percent said they eat more, but 73 percent said they snack more. Across 54 studies, stress went along with slightly more unhealthy food and slightly less healthy food. Results vary person to person.
There's some truth in it. Cortisol does play a part in where the body stores fat, and a rare medical condition where the body makes far too much cortisol moves fat to the middle. But it doesn't tell the whole story. Stress also changes how people eat and how they sleep, and both of those affect weight and waist size.
Take a 15-minute walk first, then decide. In one study of 78 regular chocolate eaters, the ones who walked before desk work ate about half as much chocolate as the ones who rested. A minute of slow breathing can help you feel calmer before you decide about the snack.
On average it does. When 11 studies that cut people's sleep short were pooled, people ate about 385 more calories the next day and didn't burn any more. Stress also makes it harder to sleep, so a stressful day can carry into the next day's eating.
One we hear a lot across the desk: "I'm not even hungry when I'm eating it." That matches what stress does. In the first few minutes of stress, appetite often drops. That's adrenaline. If the stress keeps going for hours or days, a second hormone, cortisol, stays up, and cortisol does the opposite. It raises your appetite, and what you want is often food with a lot of calories in it.
Part of this picture comes from animal research, but the cortisol part has been tested in people. In one study, 16 healthy adults had their cortisol raised overnight to a stress-like level, and on another night they got a placebo. They woke up hungrier after the cortisol night. In another study, 59 women went through a stressful session in a lab, and the ones whose cortisol rose the most ate more afterward.
So when you want chips or something sweet after a hard day, that fits what cortisol does. It doesn't mean your body needs food.
Stress doesn't make everyone eat more. When 212 college students were asked what stress does to their eating, 42 percent said they eat less overall and 38 percent said they eat more. But 73 percent said they snack more, and they said they eat fewer regular meal foods like fruit, vegetables, meat and fish.
From a survey of 212 college students. This is what they said they do.
A study that had people write down what they ate found the same pattern. When 422 workers kept a diary for four weeks, their stressful days had more high-fat, high-sugar snacks between meals and fewer main meals and vegetables. Trouble at work and trouble with other people went with more snacking. A pooled analysis of 54 studies found that stress went along with slightly more unhealthy food and slightly less healthy food. How much it changes varies from person to person.
Two common clues that an urge is stress and isn't hunger: it comes on all at once, and it's for one specific food. Hunger usually builds slowly, and most foods would do. These are clues clinicians use.
One we hear a lot: "The second I get stressed, I reach for food." Neither of these asks you to skip the snack. They put a few minutes between the stress and the food, and then you decide.
In one study, 78 people who ate chocolate regularly went two days without it. Some took a brisk 15-minute walk and the rest sat quietly, and then they all did desk work with a bowl of chocolate next to them.
Average chocolate eaten during the desk work, in grams.
Take a slow, full breath in through your nose.
Without letting it out, take one more short breath in on top of it.
Let it all out slowly through your mouth. Keep going for about a minute.
The walkers ate about half as much chocolate. The study also gave some people a harder task to make the desk work more stressful, and that didn't change how much chocolate they ate. The walk did. Two other studies found that a 15-minute walk lowered cravings for sweets, and in one of them the cravings stayed lower when a stressful task came afterward. For the breathing, a Stanford study found that five minutes a day improved people's mood, and another study found that one minute helped people feel calmer a few minutes later. Use the breathing to settle down, and use the walk when it's the snack you're trying to get past. Results vary person to person.
Stress and sleep are tied together. In a national survey of 1,568 adults, 47 percent said stress had kept them awake at night, and 37 percent said they had skipped a meal because of it.
The first figure is from a 2009 survey of adults. The second is from a pooled analysis of 11 studies.
The second link has been tested directly. When 11 studies that cut people's sleep short were pooled, people ate about 385 more calories the next day than they did after a normal night, and they didn't burn any more. They ate more fat and less protein. We see this in the clinic too. Stress and short sleep make a huge difference in how people eat, which is why we ask about both at follow-ups. Results vary person to person.
Two we hear a lot: "When I'm tired, I want sugar and carbs all day" and "I can't sleep, so I end up in the kitchen." If this is you, the sleep article covers what to do about the night itself.
The skipped meal matters too. Two more we hear a lot: "I'm good all day, then I fall apart at night" and "I don't eat all day, then eat everything in sight at night." In the diary study, stressful days had fewer main meals and more snacks. When evenings are the hardest part, we go back over the whole day with you: what you ate, whether you skipped a meal, and how you slept the night before. Regular meals with protein earlier in the day are the first thing to try, and the protein article has the numbers.
One we hear a lot: "It's my cortisol. Stress makes my body hold onto belly fat." There's some truth in it, but it doesn't tell the whole story.
Cortisol does play a part in where the body stores fat. The clearest example is a rare medical condition where the body makes far too much cortisol. It affects about 40 to 70 people in a million, and it moves fat toward the middle of the body. It's found with medical testing, and it's a different thing from everyday stress.
Cortisol shows up with everyday stress too. Researchers can measure cortisol in hair, which shows the level over a period of months. In one study of 2,527 adults aged 54 and older, people with higher hair cortisol had slightly larger waists and slightly higher weight. A pooled analysis covering more than 26,000 people found the same link. These studies measured cortisol once, so they can't tell which came first, and carrying more weight may itself raise cortisol.
Stress also changes how people eat and how they sleep: what they snack on, whether they skip meals, and how long they sleep. All of those affect weight and waist size.
Another we hear a lot: "I'm eating less, but stress is making me hold onto weight." Stress can be part of it. When eight long-term studies were pooled, job stress by itself wasn't clearly linked to gaining weight, which is why eating and sleep are worth looking at first. Results vary person to person.
Two more we hear a lot: "I already blew it today, so I might as well keep going" and "I'll just start over tomorrow." If you ate something you didn't plan to, the next meal is the place to pick back up. You don't have to wait until tomorrow.
Another is "After the day I've had, I deserve something." You probably do. It doesn't have to be food every time, and when it is food, you can decide on it instead of ending up there. That's what the walk and the minute of breathing are for. When stress eating comes up, we pick one thing to try before your next visit.
If you often eat a large amount in a short time and feel like you can't stop or control it, that's worth bringing up at a visit.
Pick one. When you're stressed and heading for a snack, take a 15-minute walk first, and if you still want it when you get back, have it. Try one minute of slow breathing when the day gets to you. Pick a bedtime tonight and set an alarm for it. One more we hear a lot is "If it's in the house, I'll eat it," so if there's one snack you always end up at, try keeping it out of sight for a week. If stress is getting in the way of eating the way you want to, a clinician-supervised weight-loss program at Optimized Health starts with a comprehensive clinical evaluation, and at your first visit we go over what you eat and drink on a normal day. We see patients in Joplin and by telehealth in MO, KS, IA, UT, and WA. Results vary person to person. Consistency over intensity.
Where this comes from: the student survey is Oliver and Wardle, Physiology & Behavior, 1999; the workplace diary study is O'Connor and colleagues, Health Psychology, 2008; the pooled analysis of stress and eating is Hill and colleagues, Health Psychology Review, 2022; the overnight cortisol study is Bini and colleagues, NeuroImage: Clinical, 2022, and the lab stress study is Epel and colleagues, Psychoneuroendocrinology, 2001; the chocolate and walking study is Oh and Taylor, Appetite, 2012, with the craving studies by Taylor and Oliver, Appetite, 2009, and Ledochowski and colleagues, PLoS One, 2015; the breathing studies are Balban and colleagues, Cell Reports Medicine, 2023, and Riedl and colleagues, Anxiety, Stress, & Coping, 2026; the sleep figure is Al Khatib and colleagues, European Journal of Clinical Nutrition, 2017; the survey of adults is the American Psychological Association's Stress in America survey, 2009; the hair cortisol findings are Jackson and colleagues, Obesity, 2017, and van der Valk and colleagues, Obesity Reviews, 2022; the job stress analysis is Kivimäki and colleagues, International Journal of Obesity, 2015; the figure for the rare cortisol condition is from the National Institute of Diabetes and Digestive and Kidney Diseases. Full citations are in the campaign claims register.
If stress or short sleep keeps pulling you off your plan, schedule a visit. At your first visit we go over what you eat and drink on a normal day.
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