Why is it so much harder to eat healthy, get up and exercise, and stay energized and focused in the winter months? It turns out there is a biological reason our bodies feel more fatigue and seek high-calorie foods, related to a little-known stress hormone that gets triggered when the days get shorter, in a naturally occurring process known as "circannual changes."

When your brain perceives the shorter days are coming, or are upon us, it triggers a hormone that programs us to be hungrier, less energetic, more inclined to hit snooze and reach for comfort foods this time of year. Here's how winter weather affects our diet, our mood, our sleep habits, and drives up constant cravings for starchy foods and alcoholic beverages. If you're reaching for carbs, it is not just your lack of willpower. Blame it on the weather and lack of sunlight.

Winter light and cravings

How our bodies react to the annual tilt of the Earth's axis away from the sun is a matter of biology. Our brains anticipate the shift as the afternoon sunlight gets shorter, which in turn triggers stress hormones called glucocorticoids that create a seasonal shift in the "food-seeking" hormone ghrelin, as well as the satiety hormone leptin, which also regulates the body's fat storage.

Studies have found that our brains react to this seasonal shift in light by directing us to eat more calories, in the form of starchy, heavy calorie-dense foods that slow us down and could, once upon a time, have helped us move less and burn fewer calories, aiding our survival odds until spring returned. So you can say we are pre-programmed to eat differently in winter, which in turn affects our mood, our energy levels, and resting metabolism making it that much harder to lose weight this time of year.

Call it the hibernation effect, but as much as we all want to listen to our bodies, this is one engrained behavioral shift that you can, and should, do your best to counteract. Here's how to eat to beat cravings, and counteract winter weight gain, by choosing foods you would ordinarily eat in the spring and summer months.

How to eat to be healthier and energized

Instead of eating starchy high-calorie foods, try to eat and exercise as if it were spring or summer, meaning fill your plate with fruits, leafy greens, and other high-nutrient foods to help combat the winter blues. Starchy foods and animal fat leave you feeling sluggish, whereas plant-based foods that are nutrient-dense and high in fiber will do the opposite.

Just by eating and acting as if it were spring, according to the experts, you can trigger your metabolism to speed up and feel more energized. Eating leafy greens, vegetables, fruit, nuts, seeds, and legumes will energize you and make it less of a struggle to get up and exercise or even just walk. Simply going outside, especially in the morning when you can get sunlight, is also beneficial.

Seasonal effects of winter are felt by different degrees

While winter isn't the same everywhere, giant swaths of the country are under a winter weather advisory, making it harder than ever to eat healthily and have the energy to exercise. The stress hormones are triggered when you perceive that there are fewer hours of sunlight, according to research. So even if you live in the southern United States, these shorter daylight hours will still affect you, but possibly to a lesser degree since you live closer to the Equator. We're animals just like bears and other creatures that slow down in winter to preserve energy and make it through the season until we can emerge when spring comes back around.

Studies show that getting sunlight in the morning resets your circadian rhythm, and the CDC recommends getting early morning sunlight to help you go to bed earlier, which can also help you not binge on sugar and starch the next day for ready energy. The research on light and your sleep and mood have been studied, but the secondary effect is also true: If you are not sleeping and your mood is depressed, you will reach for all the wrong foods.

Even indoor light impacts our eating patterns. In a study of diners in a dim room, those who were eating in the lowest light ate more calories than those eating in brighter surroundings a recent study found. Half the diners were seated in dimly-lit rooms, and half were seated in well-lit areas. Those eating in low light ordered 39 percent more calories while people in bright surroundings were up to 24 percent more likely to choose healthy menu items and eat more vegetables.

What to eat to have your healthiest winter

Here are seven foods to be healthier this winter, curb cravings, boost your immune system, have more energy, and avoid winter weight gain.

1. Vitamin C

Vitamin C has been studied ever since Linus Pauling, a chemist and doctor who won the Nobel Peace prize in 1954, suggested that large doses of C (upwards of 2,000 mg) could cure everything from the common cold to cancer. Since then we've learned that you don't need that enormous amount a day, just an orange in the morning and you're well on your way.

Vitamin C is known to help protect you against colds and flu, but it also works to boost your immune system in general, which helps fight off COVID-19 and other viruses. Aim to get at least 90 mg of vitamin C a day.

Some of the best foods for vitamin C are:

  • Red or yellow peppers
  • Oranges
  • Grapefruits
  • Kiwifruit
  • Papayas
  • Acerola cherries
  • Strawberries
  • Lemons
  • Limes
  • Brussels sprouts
  • Kale
  • Spinach
  • Broccoli
  • Parsley

Read More: The 13 Best Foods to Boost Your Immune System

2. Vitamin D

There's no question that Vitamin D is one of the most seasonally sensitive nutrients since as the sun spends more time out of view, you don't get the usual vitamin D that you would when spending hours outside in the summer sunshine. Still, even if it's brief, try to get into the sunshine for your health, especially in the morning, since spending time in sunlight early in the day helps reset your circadian clock, studies show, so you will sleep better that night.

Vitamin D is in very few foods naturally so most of us get it through drinks that have been fortified with vitamin D, from orange juice to milk. So you probably have to take a supplement to get your daily recommended value. You need 600 IU daily until you're 70 years and then it goes up to 800 IU daily.

Read More: 7 Reasons to Make Sure You Get Enough Vitamin D, According to Doctors

3. Iron

Iron helps your immune system create new cells to go out and fight off infections. But beyond worrying about immunity, iron is also a helper to build red blood cells to allow your blood to carry needed oxygen out to the body to exchange it for CO2. So when you're fatigued you may have a low iron count, which makes it harder for the body to deliver the oxygen that your cells need. Here are foods with iron.

The best plant-based sources of iron are:

  • White mushrooms
  • Lentils
  • Potatoes
  • Cashews
  • Tofu

Read More: How to Get Enough Iron When You’re Following a Plant-Based Diet 

4. Zinc

Zinc has the ability to help your body fight off colds and infections, studies show, and it can even shorten the duration of symptoms when you get sick, leading many people to take zinc all winter, to help their immune system fight off any virus or cold. The Mayo Clinic confirms that taking zinc within 24 hours of getting sick can shorten the duration of a cold or virus by days.

The top plant-based foods for zinc are:

  • Tofu
  • Hemp Seeds
  • Lentils
  • Oatmeal
  • Pumpkin Seeds
  • Shiitake Mushrooms
  • Black Beans
  • Green Peas
  • Cashews

Read More: The 10 Best Foods for Zinc to Boost Immunity, By an RD. 

5. Plant Protein (avoid animal fat)

Choose plant-based proteins such as legumes and tofu, since these allow your body to get the protein it needs, but avoid animal fat in red meat and dairy, which can cause inflammation. Studies show that animal fat is inflammatory for most people, causing Inflammation that is a precursor to many lifestyle diseases. So the more you eat plant-based the better for your all-around health.

Foods that cause inflammation include red meat, hot dogs, pepperoni, salami, deli meats, and sausage, according to studies. The World Health Organization has classified these meats as carcinogens on the same level as tobacco smoking. How does that affect your winter diet? Chronic systemic inflammation is detrimental in the short term, creating more work for your body to move, circulate blood flow, and function optimally on a cellular level.

Studies show that Inflammation can cause changes in our cells' DNA, which elevates the long-term risks of cancer, as well as Alzheimer's and auto-immune diseases where the body attacks its own healthy cells. It appears to also play a role in heart disease, and other signs of aging. To lower your body's inflammation levels naturally and reduce the health risks, fill your plate with high-fiber, nutrient-dense foods, according to the Harvard School of Health such as lentils and pulses.

The top 10 sources of plant-based protein are:

  • Seitan
  • Tempeh
  • Lentils
  • Hemp Seeds
  • Tofu
  • Edamame
  • Quinoa
  • Black Beans
  • Amaranth
  • Peas

Read More: Want to Lower Risk of Disease? Eat to fight Inflammation

6. Omega-3 Fatty Acids

The most important thing to keep in mind when eating fat is the ratio between unhealthy fat and healthy fat, which is also known as omega 3. The more omega 3 you get the better to lower inflammation in the body. The number one source of omega-3 fatty acid is fish oil but if you avoid fish, you can get it from plant-based sources like seeds.

Omega 3 comes in three different types: EPA, DHA, and ALA. Both EPA and DHA are found in fish oil and algae, but ALA is mostly found in whole, plant foods such as nuts, beans, and other legumes. Think of ALA  as the building block to allow your body to get what it needs, so generally, a plant-based dieter needs to eat more of these nutrients to reach their daily recommended amount. Here are the seven whole, plant foods that will help you reach your daily recommended amount of Omega-3, according to the USDA. 

Omega 3 fatty acids are found in:

  • Chia Seeds
  • Walnuts 
  • Hemp Seeds
  • Flaxseeds 
  • Edamame
  • Kidney Beans
  • Brussels Sprouts

Read More: 7 Best Foods for Omega 3 to Boost Mood and Fight Inflammation

7. Antioxidants in green tea

When it comes to antioxidants, green tea is a hero drink. Antioxidants are the compounds in natural foods that help your body neutralize the oxidative effects of stress and aging on the body. So this winter, to stay healthy and bolster your body's natural defenses, drink any type of tea you prefer but especially green tea.

Nothing is quite as powerful or concentrated as antioxidants found in green tea to help your body fight disease and counteract the aging process. EGCG stands for epigallocatechin gallate, which is a powerful plant compound that has several known health benefits, including reducing inflammation and helping your body fight off disease.

Macha has the highest level of EGCG of all the teas, but any green tea is a great source, as is black tea and Oolong tea. For the least processed tea, where the antioxidants have the greatest potential to remain intact, drink white tea, which gets dried and withered in sunlight, but not cooked.

For the most benefits of your tea, don't scald it, but do let it steep for a long time, since the longer you keep the leaves the better for health results. When it comes to tea, temperature matters. To maximize the health benefits of your tea, cold-steep it, which lets the leaves release their compounds into the water but keeps the antioxidants like EGCG active. Don't scald the tea, which can damage its compounds; instead heat it to 106 degrees Fahrenheit for green tea and 200 degrees Fahrenheit for black tea, according to experts at Planet Tea.

Read More: Which Tea is the Healthiest? The Benefits of the Most Popular

 Read More: The 6 Benefits of Green Tea

And: For immunity and Natural Weight Loss, Drink This Type of Tea, Studies Say. 

And 3 things to do that will help you be healthier all winter

1. Exercise in the morning. To reset your body clock, get outside in the morning. First of all, when you get up and strap on running shoes or do any type of heart-thumping activity, you are training (or tricking) your body into thinking it's spring, time to be active, and jumpstart your resting metabolism. Light in the morning signals to the brain that the long dark months are coming to a close. Stand with your eyes shut and look into the warm glow of sunrise for a few minutes, letting the sunlight sink into your face and eyelids, which will reset your circadian clock.

2. Take a walk by the ocean or in nature. Scientists have long known that negative ions get released by the waves crashing on the shore. These in turn can enter the body when you inhale the salt air and attach to free radicals in the body, lowering your stress. Whether at a waterfall or the ocean, when water crashes on the sand or rocks, it releases tiny charged atoms that can help neutralize the free radicals in your body.

While these studies sound out there, scientists have long believed that the way our bodies interact in nature – including in forests and mountains, where there is an abundance of charged ions – has a healing effect on our cells, by helping counteract stress. If you've ever stood by the seashore and inhaled deeply or sat by a waterfall and watched the cascading white water and felt your body shed stress like a winter coat, you know there is some truth to it.

Plan a getaway for a few sun-filled days. If possible, or get outside and into nature on the weekends. Whether you love the mountains or the beach, cross country skiing or swimming in the warm ocean, or just walking in a beautiful place, treat yourself to a day off or get outside into the natural world whenever you can manage to do it for a few hours or longer. Studies show that spending time in nature resets your biological clock to be more positive, fight off depression and help you focus.

All of this makes the need for sugary or starchy foods less acute (since you won't feel the need to self-medicate with carbs). So if it's realistic, plan a mini vacation. Or just get into the habit of meeting friends for a weekend walk in a beautiful location.  However you do it, try to break up the winter months with something joyful and preferably active!

Bottom Line: Winter affects our eating habits. Here's how to eat to counteract it.

When you feel sluggish or are craving all the wrong foods that are high in calories and low in nutrients, the best way to counteract it is to eat like it's spring, with big grain bowls, salads and soups full of vegetables, whole grains, as well as fruits, nuts, and seeds. Keep your energy up and get outside in the morning to get your daily exercise. You will feel better!

More From The Beet