Can Being in a Calorie Deficit Cause Headaches? (explained)

calorie deficit causing headaches man with headache

There is a lot of debate about whether or not being in a calorie deficit can cause headaches. Some people believe that this is definitely the case, while others think it’s just a coincidence and there are other factors at play.

Now, let’s get down to the details and examine this topic and try to answer the question once and for all if your calorie deficit is to blame for your headaches.

Can being in a calorie deficit cause headaches?

There are actually many factors that can cause headaches, a calorie deficit could be one of them for various reasons, but these reasons may not be what you expect.

As we have discussed in previous posts, a calorie deficit occurs when you burning more calories than you consume to lose weight. This can happen because of exercise, restricting calories only without exercise, or a combination of both.

When you are in a calorie deficit, your body has to find a way to make up for the lost energy. It does this by breaking down stored fat and using it for fuel. This is how you lose fat by being in a calorie deficit.

You can only lose weight by being in a calorie deficit, but it must be done correctly and safely.

When a calorie deficit is too restrictive, you may begin to suffer from headaches.

The real culprit that is causing the headaches is not the simple fact of being in a calorie deficit, but the amount of calories you are consuming, and the quality of the foods you are eating.

Your calorie deficit may be too extreme and cause headaches

Girl with headache. Can being in a calorie deficit cause headaches?

If you are consuming too few calories, you are not in any way giving your body the nutrients and energy that it needs to function.

You should never restrict calories to dangerously low amounts to lose weight faster.

It is ALWAYS best to lose weight at a slower, healthier pace of about 1-2 pounds per week.

You will have slower results this way, but they will last and you will adapt to living a healthier lifestyle, not living a diet lifestyle.

Losing weight at a slower pace will be more sustainable for you, and it will be more enjoyable.

You’re not consuming enough protein

Not eating enough protein in your calorie deficit can lead to dehydration and electrolyte imbalance, both of which can cause headaches. Protein is also important because it helps you maintain lean muscle mass while in a calorie deficit.

We always want to consume adequate amounts of protein.

You’re not consuming enough fat

If you are eating a very low-fat diet, this can lead to headaches because you are not getting enough essential fatty acids. These are important for maintaining cell membranes, which can become damaged when you don’t have enough of them.

Not all fat is bad. Healthy fats such as monounsaturated and polyunsaturated fats actually prevent many types of disease, so make sure to eat foods with healthy fats, such as fish, and certain oils.

You’re not consuming enough carbohydrates

If you are restricting carbs too much, this can also lead to headaches. Not consuming enough carbs can cause your blood sugar levels to drop, which can lead to hypoglycemia (low blood sugar) which in turn, can cause headaches.

This is because your body needs glucose for energy and if you don’t have enough on hand, you may experience headaches. Low blood sugar can lead to changes in hormones such as epinephrine and norepinephrine. These changes can affect blood vessel behavior in the brain, causing you to develop a headache.

Your brain needs glucose to function adequately. Carbs are not the enemy, and you can still lose weight by consuming carbohydrates.

In a diabetic person, one of the signs that their blood sugar is low is a headache. It is your body’s way of telling you that the amount of carbohydrates on deck are not enough.

You need to consume healthy amounts of carbohydrates from sources like sweet potatoes, grains, and other vegetables, not simple carbs from lollipops and cupcakes.

I want to stress that having a cupcake or a lollipop is perfectly acceptable, in moderation, but carbohydrates from healthy sources will actually HELP our bodies.

Do not think of your calorie deficit as a negative restriction. Moderation is key.

You’re eating unhealthy foods

Processed foods have been linked to headaches.

The preservatives that are in many types of processed foods can react differently with different people. Everyone’s body can react in a different way to certain types of preservatives.

This is mainly because they can cause inflammation. In general, the best way to avoid headaches while in a calorie deficit is to make sure you are consuming enough healthy calories from whole foods.

processed foods causing headaches

You need to drink more fluids

You should always remember to drink plenty of water or another healthy type sports drink low in calories with adequate amounts of electrolytes.

Dehydration can cause headaches as well. It is important to stay hydrated to avoid headaches and also keep those kidneys functioning at their best.

Are there other factors that can cause headaches when in a calorie deficit?

Vitamin deficiencies can cause headaches

Magnesium, Vitamin D, and Vitamin B12 are all vitamins that keep us healthy and not having enough of these vitamins can cause headaches.

Make sure you are getting enough vitamins by eating a well-rounded diet with plenty of fruits and vegetables. You may also want to consider taking a multivitamin supplement.

Electrolyte imbalances

Common electrolytes that are important to keep our bodies functioning at their best are sodium, calcium, and potassium.

Electrolytes are important because they perform a vast array of vital functions in our bodies such as helping our heart to contract, helping muscles to contract, and regulating our fluid volume.

When we are dehydrated, we can throw many of these electrolytes off kilter.

How can you prevent or alleviate headaches if you are in a calorie deficit?

Do not create a calorie deficit that is too strict

You need to create a calorie deficit that is acceptable for you and where you will be losing 1-2 pounds per week at a slower pace. A good estimate is to take your goal bodyweight, and multiply by 12.

The number you get is a rough estimate of the amount of calories you can start with per day. Try it for a week, see how you feel, and if it works and you feel good, you can keep this amount. If it is not working, you can adjust.

Sometimes creating the perfect calorie deficit range is trial and error.

This is ONLY an estimate. If you want to create a calorie deficit to try based on your BMI or TDEE, see this article on how to create a calorie deficit.

Drink more fluids, especially water

As we discussed, fluid balance and drinking fluids is so important. It helps to keep us hydrated and our kidneys healthy. It also helps us to keep our electrolytes in the correct ranges for organ function.

Drink water and you can eat plenty of high water content veggies.

water to prevent headaches in a calorie deficit

Make sure you’re getting enough protein, fat, and carbohydrates

These are essential for body function and building muscle as well. I do not think it is a good idea to restrict either proteins, fats, or carbs. You should be consuming adequate amounts of each.

Eat healthy foods and avoid processed foods

I know processed foods are sometimes hard to avoid. We are a hard working society and sometimes it is hard to find the time to eat organic healthy foods all of the time.

If you do need to consume processed foods, make sure to do this in moderation and not consume them at every single meal. As I said, we should never be restricting ourselves and NEVER having the foods we like.

If you feel the preservatives that are in many processed foods might be the cause of your headaches, try to consume less of them.

Consider taking a multivitamin supplement

Vitamin supplements can be great for many individuals and there are many great, affordable options out there.

A vitamin supplement may be what you need to help you make sure you are getting the right amounts of essential vitamins and minerals.

Of course, if you are having frequent headaches or have questions about starting supplements or even if a calorie deficit is right for you, it is best to consult with your doctor to rule out any other serious underlying causes of headaches and any concerns you may have.

Headaches can be caused by many different things and it is always best to be safe than sorry. If you ever have any doubts about what is acceptable for your health, it is smart to talk with your doctor first, they are there to help you.


To conclude, being in a calorie deficit can cause headaches for some people, if done incorrectly.

If you are in a calorie deficit and experiencing headaches, make sure to use the helpful steps above as guidance.

If you ever have any doubts about what is normal for you and your body, it is smart to talk with your doctor or other healthcare professional.

Headaches can be caused by many different things that may not be discussed here, and it is always best to stay on the safe side when it comes to your health.

As always, I wish you the best in your weight loss and health endeavors. I know you can do this!