Feeling Cold On Keto: Here’s Why & Tips To Quickly Fix It

When I first tried the Keto diet, I can clearly remember how cold I felt in the first few days. What made the story stick in my mind was that it happened during the spring. My roommates were complaining about how hot the weather suddenly had turned, and I was like, “No. It’s freezing.” I’ve dug deep into it since then and I’ve got all the answers you need.

So Why Do We Feel Cold on the Keto diet and\or Intermittent Fasting?

Feeling cold is common when transitioning to a ketogenic diet or intermittent fasting, often due to the body adapting to fat burning and reacting to a caloric deficit. This symptom, similar to the ‘Keto Flu’, typically subsides within a week.

In this article, we will discuss the reasons behind this phenomenon, whether it requires your attention, and tips to get over it soon.

To understand why this is happening to you, if you’re attempting the Keto diet and\or Intermittent Fasting, you have to think about how these diets work. As I’ve stated in previous articles, in order to lose weight, there’s no going around the following equation:

Calories Needed VS. Calories Consumed

You might think, “Duh, who doesn’t know that?” But you’d be surprised how many people neglect this equation when trying to lose weight. Keto is not a magic tool to lose weight. Neither is Intermittent Fasting. They are a tool to help you play with this equation to achieve your weight goals. Let me explain a bit.

  • Keto makes you, to an extent, independent on food. There are crucial vitamins and nutrients you still need to be eating every day. However, it is not as big of a problem not to meet your calorie needs religiously daily.

    This is because when you’re in ketosis, your body can take the energy it needs out of your fats by converting them to Ketones. That’s why you don’t feel hungry on Keto.

    Not feeling hungry helps you eat less, which helps your body burn more of its stored fats, and thus, you lose weight.
  • Intermittent Fasting has a similar approach. It can manipulate your hormones. Don’t take “manipulate” in a negative context. It’s actually for your own sake here.

    It helps your body secrete more Growth Hormone and less Insulin. This can help you increase your metabolic rate and make you feel hungry less often.

So Where Does Feeling Cold Fit Here?

You’re probably wondering, what does that have to do with me being cold? Well, the transition to either or both of the aforementioned diets requires time. In that time, especially if you’re doing a calorie deficit before you’re fat-adapted, your body will think, “Wait, I’m not getting enough calories. I can barely do the important stuff. So I won’t waste energy on warming up the skin.

And your body is right to think that. Many processes are happening in your body that require energy that are more important than feeling warm.

Is Feeling Cold a Sign Of Ketosis?

Feeling cold in the early stages of doing Keto or Intermittent Fasting can be a sign of the ongoing fat adaptation process and not a sign of being in a full-blown ketosis state. Once you reach that state, you will notice this feeling going away, along with other signs of Keto flu you might have.

Additional Reasons Why You’re Feeling Cold While On Keto

1- Thermoregulation and Reduced Body Fat

The process of losing body fat through the ketogenic diet has a significant impact on body insulation. Adipose tissue, more commonly known as body fat, serves multiple functions, one of which is acting as a thermal insulator, safeguarding the body against heat loss.

With a substantial reduction in adipose tissue, the body’s thermal insulation decreases, potentially leading to increased sensitivity to cold temperatures.

This was something I noticed myself after losing weight on keto, as well as hearing it from many clients who did the diet. One client said she had never worn this many sweaters in the spring.

We found that introducing more warm beverages and a mild exercise routine helped with these changes, which eventually stabilized as our bodies adapted.

2- Metabolic Shift and Its Effect on Body Temperature

Transitioning from a glucose-based metabolism to a ketone-based metabolism, which is a fundamental characteristic of the ketogenic diet, might alter body temperature regulation.

The body shifts to using ketone bodies produced in the liver from dietary fats as a primary energy source. This metabolic adaptation is called nutritional ketosis and while beneficial for weight loss, it might also lead to a feeling of being cold.

The exact mechanism for this is still under investigation, with potential causes being changes in blood flow or alterations in metabolic rate.

Having guided several clients through the transition from a glucose-based to a ketone-based metabolism, it became apparent that some of them experienced these temperature regulation changes. A long-term client who finally decided to try out keto, told me, “I didn’t expect to feel this cold in the middle of summer!”

Ensuring the body was adequately nourished, especially with fats, and recommending a regular light exercise regimen helped him adapt to this transition phase.

3- Thyroid Function and Body Temperature

Thyroid hormones play a crucial role in controlling metabolic rate, which directly impacts body temperature regulation. Keto may alter thyroid hormone levels, particularly triiodothyronine (T3), which is the most active thyroid hormone and plays a vital role in thermogenesis (heat production).

If T3 levels decrease, a drop in metabolic rate could lead to lowered body temperature, making us feel colder. However, this topic is complex and requires further research for a definitive understanding.

4- Muscle Mass Changes and Thermogenesis

Muscle tissue is a primary site for thermogenesis, and its loss could potentially influence body temperature regulation. While keto is primarily designed to burn fat, it can sometimes lead to muscle mass reduction, if protein intake is not adequate.

A decrease in muscle mass can result in reduced heat generation, contributing to an abnormal sensation of coldness.

The way I go about this with clients is to increase their protein intake and incorporate resistance training into their routine to minimize muscle loss, which gradually improves their situation.

5- The Role of Dehydration in Thermoregulation

The effects of dehydration were more prominent than I initially anticipated. I personally found that forgetting to replenish lost fluids made me feel not just cold but also lethargic.

That’s because proper hydration is essential for maintaining core body temperature. Inadequate fluid and electrolyte balance can disrupt our body’s ability to regulate heat, causing an increased susceptibility to cold.

It’s crucial for anyone who eyes starting to do Keto to maintain appropriate hydration and electrolyte levels to ensure optimal body function, including temperature regulation.

How Long Does Feeling Cold Last On Keto and\or Intermittent Fasting?

Feeling abnormally cold on Keto or Intermittent Fasting lasts averagely a week. However, it depends on your age, metabolic rate, and whether or not you have been in ketosis before. Thus, it can last between a couple of days and a few weeks.

The most important factor that can dramatically reduce how much this stage lasts is having been on one of these diets before. Your body, then, would be able to bounce back a lot quicker if it has reached the state of fat adaptation before.

The first time is always the hardest.

That being said, I’ve also noticed a significant gap between people of different age groups in regards to how long this stage lasts.

Young people tended to go into fat-adaptation faster and with little to no side effects. Even the Keto-Flu symptoms were much more insignificant. This also ties to the third factor I mentioned, the metabolic rate. When it’s high, you need less amount of time to reach the state of ketosis and you go through fewer side effects.

In fact, I went on to to do some polls for Keto dieters, and 74.1% of those who said they encountered this symptom on Keto were above 45 years old. And 77.9% of those were women. (It’s noteworthy to mention that the majority of the people within the group polled were women.)

Should You Worry About Feeling Abnormally Cold on Keto/Intermittent Fasting?

If you’re feeling cold in the very early stages of the diet, you should know that it’s part of the process. However, if the other symptoms of the Keto flu resolve and this one persist well beyond getting into ketosis, then you should be looking deeper into it.

If you’re also experiencing other symptoms that your physician has not prepared you for, you need to call them.

As you have already consulted your physician before you started the diet, be sure to always stay in contact with them over any concerns you might have.

That being said, making sure you’re following science-based guides is crucial to ensure that you’re always on the right track.

Tips & Tricks To Help You Get Over It Faster

  1. Combine Both Keto and Intermittent Fasting. This can accelerate the process considerably. It will allow your body to adapt faster and more efficiently because you’re allowing it to play the hormones game of GH and insulin and, at the same time, you’re pushing it to start using ketones instead of glucose. If you are gonna go with both Keto and Iitermittent Fasting I suggest you also do the following tip:

  2. Increase Your Healthy Fat Intake. If you’re doing both Keto and I.F., chances are you will be hungry all day at first. So make sure to give your body enough energy sources.

    Since it’s not getting the carbs it is used to getting, you should help it find its new energy source: fat. It can be a struggle, at first, to get enough fat in a short window of time (assuming you’re doing I.F.). That is why suggest you also go with the third tip:

  3. Drink Bullet Proof Coffee. I mean, this coffee is just beyond me. I’m afraid that once you try it, you’ll never want to look back and prepare it yourself. This is how obsessed I know you’ll be with it. Have a look at it here on Amazon.

    This is an excellent drink to have at this point. Not only can it help you get more healthy fats into your body, it can also be consumed in your fasting window. Thus, it makes it easier for you to stick with both Keto and I.F. Plus, iIf your prepare it well, it can have an amazing taste.

    I highly recommend Bullet Proof Coffee at both the early and late stages of the diet. At the early stages, it helps you meet your caloric/fat goals easily. At the late stages, it can be an amazing part of the diet if you want that extra calorie intake because you reached your weight goals and no longer need to be in a caloric deficit.

    However, in the middle stage, when you’re struggling to lose weight, it’s not highly recommended to be drinking a cup of coffee that has this much calories.

  4. Drink More Water Than Your Body Ask For. The reason I say that is that it’s hard at this stage to give your body enough water, so you’re always giving it less than it needs. That’s why when you aim to give it a tad more, you end up giving it just enough.

    Your body is going through a lot water secretion in this phase, and dehydration is a big cause of all the symptoms of the Keto Flu. So, getting enough water can be crucial to get rid of those symptoms.

  5. Aim At Getting 7 Hours of Sleep. If your schedule allows you to have more, go ahead. But don’t go under 7 in this phase.

  6. Replace Potassium, Sodium and Magnesium. There are other electrolytes you should be looking into, but these are the most important. The Keto Diet restricts a lot of foods that are rich in Potassium, for example. These are things like fruits, starchy vegetables and beans. So in order to get the potassium you need you should be adding new foods to your daily routine, such as leafy greens and avocados.

    Same thing for Sodium. Especially due to the fact that when insulin levels start to go down, the kidneys secrete more sodium. So making sure to properly salt your food in this period can be of great help.

    As for Magnesium, there is a big range of alternatives you can get it from. Avocado, dark chocolate, salmon, almonds and spinach are a few popular examples that Keto-friendly.

    If you’re struggling to get enough electrolytes from whole foods, this product can be amazing. It has personally helped me meet my micronutrients goals at many periods of my life recently.

  7. Make Sure To Exercise (But Take it Easy) Exercise is an amazing way to tell your body that you are OK. That you are having that caloric deficit on purpose. It realizes that it shouldn’t go into the Desert Mode, where it slows your metabolism down to keep you safe.

    On the other hand, you should note that doing heavy lifts and going with your exercise to the extreme can do you more harm than good in this phase.
  8. For the Ultimate Keto Lifestyle Tips, Meet the Doctor Behind This Blog On YouTube!

Allow me to be part of your journey, and to offer you constantly tips and hacks you can apply on Keto to resolve the issues you might come across, achieve the results you want and deserve, and have keto continue to transform your life.

I’ll see you on YouTube!


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Nabeel Kallas

I'm a medical doctor with a lot of passion for Keto & Intermittent Fasting. They have completely changed my life and I am beyond honored to help you experience that same change. I'm ready when you are. Read more here.

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