If you find yourself hunting for candy when you’ve had a stressful day, you’re not alone. Comfort food is a common go-to when we’re under pressure. Unfortunately, the combination of stress and high-calorie comfort food alters the brain and can lead you to eat too much. It may also increase cravings for sweet, highly palatable foods, which could lead to weight gain.

Scientists from the Garvan Institute of Medical Research in Sydney discovered that stress trumped the brain’s normal response to satiety, leading to constant reward signals that promote the consumption of very palatable food. This was observed in the lateral habenula, a part of the brain that when activated typically decreases these reward signals.

"Our findings reveal stress can override a natural brain response that diminishes the pleasure gained from eating -- meaning the brain is continuously rewarded to eat," says Professor Herzog, senior author of the study and Visiting Scientist at the Garvan Institute.

His team found that chronic stress and the addition of a high-calorie diet, may result in more and more food intake plus a penchant for sweet, highly palatable food, which promotes weight gain and obesity. His research raises awareness at how important a healthy diet is in times of stress.

The research was published in the journal Neuron.

Your brain when stressed

Some people lose their appetite when under stress, but most will eat more foo than normal and pick calorie-dense options high in fat and sugar.

To evaluate what motivates these eating habits, the researchers used mouse models and investigated how various areas of the brain react to chronic stress under various diets.

 

 

 

"We discovered that an area known as the lateral habenula, which is normally involved in switching off the brain's reward response, was active in mice on a short-term, high-fat diet to protect the animal from overeating. However, when mice were chronically stressed, this part of the brain remained silent -- allowing the reward signals to stay active and encourage feeding for pleasure, no longer responding to satiety regulatory signals," explains first author Dr Kenny Chi Kin Ip from the Garvan Institute.

They discovered that stressed mice eating a high-fat diet gained twice as much weight as those on the same diet that were not under stress.

The researchers found that a chemical called NPY was at the heart of stress response. Our brains produce this when we’re under stress. When NPY was blocked from being activated in brain cells in the lateral habenula of stressed mice eating a high-fat diet, the mice ate less comfort food, which led to less weight gain.

Driving comfort eating

A ‘sucralose preference test’ was then done which let the mice choose to drink water or water sweetened with sucralose (AKA Splenda).

Mice under stress that were on the high-fat diet drank three times more sucralose than mice on the high-fat diet alone. This suggests that stress activates more reward when eating and also directly drives a craving for sweet, palatable food, according to Professor Herzog.

The preference for sweetened water was not seen in stressed mice consuming a regular diet.

Stress trumps normal calorie intake

According to Herzog, "In stressful situations it's easy to use a lot of energy and the feeling of reward can calm you down -- this is when a boost of energy through food is useful. But when experienced over long periods of time, stress appears to change the equation, driving eating that is bad for the body long term,

These findings suggest that stress is an important regulator of eating habits that can trump the brain’s natural way of balancing calorie requirements.

Professor Herzog notes, "This research emphasizes just how much stress can compromise a healthy energy metabolism. "It's a reminder to avoid a stressful lifestyle, and crucially -- if you are dealing with long-term stress -- try to eat a healthy diet and lock away the junk food."

Nutrition tips to combat stress

When you’re under stress, your body and brain need the best “food in your food”. Below are 10 tips to keep your brain and body fueled when you’re dealing with stress.

1.    Don’t skip meals. Eating at regular times keeps you fueled to face whatever situation heads your way. Being “hangry” may increase the likelihood of grabbing snacks or treats when you’re stressed.

2.    Keep ultra-processed foods out of site. A treat or snack now and then is fine but when you’re under stress, chips, soda, fast food, and high-fat desserts can exacerbate feelings of anxiety and depression.2

3.    Water. While not “food”, drinking adequate water is so important to prevent dehydration in times of stress. Dehydration can lead to fatigue, which could trigger overeating.

4.    Fruit. Fresh, frozen, or dried fruit can curb a sweet tooth and provide fiber to help fill you up. Pair fruit with nuts, cottage cheese, or Greek yogurt for a filling pick-me-up.

5.    Veggies. Raw veggies may curb the urge to crunch on high-fat, salty snacks. Keep a variety on hand including peppers, carrot sticks, celery sticks, grape tomatoes, and more.

6.    Whole grains. Carbs get a bad rap but to be honest, avoiding them may increase stress. Whole grain carbs like rolled oats, whole grain pasta, brown rice, or quinoa provide slowly digested carbs and B vitamins for the brain to function and focus.

7.    Beans and lentils. Beans are great brain food because they give you both carbs and protein. These may help regulate your blood sugar in addition to providing zinc, magnesium, and B vitamins.

8.    Lean meat or poultry. Lean cuts of beef or poultry provide your body and brain with B vitamins and protein to stay focused. Trim the fat from cuts of meat and bake, broil, or grill to keep fat and calories in check.

9.    Fatty fish. When it comes to mental health, fish is on your side. Fatty fish such as mackerel, salmon, and tuna provide omega-3 fatty acids to help reduce inflammation. Observational studies show an association between unsaturated fatty acid intake and reduced risk of depression. 3

10.  Nuts and seeds. A study on adults and dietary patterns related to the risk of depression found that those who consumed nuts and seeds had lower depression scores.3

Lisa Andrews, MEd, RD, LD

References:

1. Chi Kin Ip, Jemma Rezitis, Yue Qi, Nikita Bajaj, Julia Koller, Aitak Farzi, Yan-Chuan Shi, Ramon Tasan, Lei Zhang, Herbert Herzog. Critical role of lateral habenula circuits in the control of stress-induced palatable food consumption. Neuron, 2023; DOI: 10.1016/j.neuron.2023.05.010

2. Shakya PR, Melaku YA, Page A, Gill TK. Association between dietary patterns and adult depression symptoms based on principal component analysis, reduced-rank regression and partial least-squares. Clin Nutr. 2020 Sep;39(9):2811-2823. doi: 10.1016/j.clnu.2019.12.011. Epub 2019 Dec 14. PMID: 32007317.

3. Gao X, Su X, Han X, Wen H, Cheng C, Zhang S, Li W, Cai J, Zheng L, Ma J, Liao M, Ni W, Liu T, Liu D, Ma W, Han S, Zhu S, Ye Y, Zeng FF. Unsaturated Fatty Acids in Mental Disorders: An Umbrella Review of Meta-Analyses. Adv Nutr. 2022 Dec 22;13(6):2217-2236. doi: 10.1093/advances/nmac084. PMID: 36041185; PMCID: PMC9776730.