We all know intermittent fasting can help you lose weight and get leaner. But the main cause of people stopping intermittent fasting is because of a phenomenon called dieting fatigue.
This problem occurs when your body is not able to generate sufficient energy from the burnt fat. The result is that many people feel tired, cold, tired, and generally unwell.
I was mucking around the internet a while back looking at intermittent fasting blogs because I’d become a bit of an intermittent fasting convert and wanted to find out more.
One thing that occurred to me when reading blogs written by people who’d tried intermittent fasting was that they reported feeling cold quite a lot, especially when it came to doing their fast in the mornings.
So, why do I feel cold when intermittent fasting? This is a question that comes up frequently in the community. I’m going to cover all common reasons as well as my personal experience with intermittent fasting and feeling cold during my sessions.
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Why Do I Feel Cold When Intermittent Fasting?
If you feel cold when fasting, it’s probably because you’ve become accustomed to your body producing heat from digestion.
When you’re digesting food, your body is working hard to break down the food and extract nutrients from it. This process is called thermogenesis, and it generates some heat that warms up your body.
When you eat frequently enough to keep your blood sugar stable, this process goes on without interruption. However, when you restrict your eating window or skip a meal or two, it stops.
This means that if you’ve been eating frequently enough to keep blood sugar levels stable (which means 4-6 meals per day), then when you do fast, your body will not have had an opportunity to adapt to not producing heat through digestion.
As such, when you start fasting, it may take a few days for your body to adjust and start generating heat through non-digestive mechanisms like brown adipose tissue (BAT) or shivering (shaking).
This is why the first few days of fasting can be difficult. It’s also why you need to make sure you’re eating enough calories so that your body has enough energy to keep up with its usual processes, which include generating heat.
Your Body Is Adjusting to the New Energy Demands
One of the reasons you are feeling cold when intermittent fasting is that your body is adjusting to the new energy demands.
Intermittent fasting increases the metabolic rate and burns more calories, but it also lowers insulin levels. This means that your body can’t store as much energy as it usually does, which results in a drop in blood sugar levels.
As a result, you might get hungry more often during this period of time and feel cold too. However, this will eventually go away after some time as your body adjusts to the new eating pattern.
The best way to deal with this is by consuming warm food and drinks such as soups or hot coffee during intermittent fasting.
Your Body Is Burning More Fat for Fuel
Another reason why you are feeling cold when intermittent fasting is that your body is burning more fat for fuel. This means that the body is going into a fat-burning mode, and this results in lower blood glucose levels.
Your body will use fat stores as its main energy source, which means that there is less glucose available to be stored as glycogen (a type of stored carbohydrate) or to be used as energy by the cells.
As such, if you feel cold while intermittent fasting, it’s because you’re burning more fat than usual.
Less Calorie-Burning Leads to Lower Body Temperature
Calorie reduction leads to lower body temperature. When you eat fewer calories than your body uses, it burns fat instead and produces ketones, which are used by the brain as an alternative source of energy. This process leads to lower body temperature, which can explain why some people feel cold when they fast.
The body responds to hypothermia by increasing the production of heat-generating enzymes, such as uncoupling proteins and the electron transport chain. These enzymes are activated when you eat fewer calories and burn fat instead. This phenomenon can explain why some people feel cold during fasting.
You Could Be Low in Iron
Intermittent fasting can be downright uncomfortable for some people, especially those who are prone to hypoglycemia (low blood sugar), have low iron levels, or have adrenal fatigue. If you’re new to IF, it may take your body a little time to adjust.
If you’re experiencing cold hands and feet when fasting, it could be caused by low iron levels or a drop in body temperature during the fast.
Iron deficiency is one of the most common nutrient deficiencies in America today due to our poor diets and lifestyle choices – especially among women. Iron helps transport oxygen throughout your body so you can stay energized and alert during your fasts.
Without enough iron, you’ll start feeling fatigued and sluggish, which will make it harder for you to complete your fasts. And if you’re feeling fatigued while fasting, then chances are that you won’t feel like working out either!
You May Be Dealing with an Underlying Health Issue
Intermittent fasting can make some people feel sluggish or tired, which can lead to shivering when they’re not getting enough calories or carbohydrates from food.
If this is happening to you, it’s possible that your body is dealing with an underlying health condition like hypothyroidism (underactive thyroid), low blood sugar levels, or chronic fatigue syndrome.
The best thing to do is see your doctor and get tested for these conditions so they can be treated accordingly.
How to Deal with Cold When Intermittent Fasting
If you feel cold while fasting, there are a few things you can do to help yourself get through it:
Drink plenty of water or herbal tea to help keep your body well-hydrated. This will also help prevent constipation, which is common when fasting.
Avoid Caffeine, Alcohol, and Exercise
Caffeine and alcohol may cause dehydration, which can make you feel colder than normal. Exercise can also cause dehydration due to sweating, so avoid it if possible during your fasts.
Eat More Calories Than Usual During Your Feeding Window
You may need more calories when fasting than in a non-fasting state because your body will be using up its stores of glucose (energy) at a faster rate than normal during your fasted state (the 12 hours of not eating).
You can use my calorie calculator here to calculate how many additional calories you should consume during each meal if this is an issue for you: https://tummy-trimmers.com/calorie-calculator
Take Supplements If You Feel Weak or Nauseous During Your Fasted State
You may find that taking supplements such as multivitamins, electrolytes, and fish oil can help reduce feelings of weakness and nausea during your fasted state.
Frequently Asked Questions
Why do I feel cold when fasting?
You might be feeling cold because your body has not yet adjusted to the fast. As you become more adapted to intermittent fasting, your body will learn how to use stored energy more efficiently and effectively.
Can I fast while pregnant?
There is currently no evidence that intermittent fasting is safe during pregnancy. However, some women do choose to fast while they are pregnant. If you decide to fast while pregnant, be sure to contact your doctor first so that he or she can monitor your progress closely.
Can I fast while breastfeeding?
There is currently no evidence that intermittent fasting is safe during breastfeeding. However, some women do choose to fast while they are breastfeeding. If you decide to fast while breastfeeding, be sure to contact your doctor first so that he or she can monitor your progress closely.
What should I eat after fasting?
It’s best to eat a meal that is high in protein and healthy fats. This will help your body begin the process of rebuilding muscle tissue, which can become depleted during fasting.
Can I exercise while fasting?
You should avoid strenuous exercise during a fast, especially if you are new to intermittent fasting. However, light activities such as walking, yoga, or stretching are fine for this purpose.
Takeaway: There are many reasons why you might feel cold when intermittent fasting, and the best way to address these feelings is to keep a record of what you eat, how much you drink, and how you feel during your fast or extended fasting periods.
If you’re feeling cold or sluggish, it could be due to low blood sugar levels or dehydration. You can fix this by adding more fat to your diet (such as olive oil) or drinking more water throughout the day.
- 9 Signs That You’re Not Eating Enough: https://www.healthline.com/nutrition/signs-of-not-eating-enough
- Thermogenesis: https://www.sciencedirect.com/topics/medicine-and-dentistry/thermogenesis
- Hypothermia: https://www.betterhealth.vic.gov.au/health/healthyliving/hypothermia
- Hypothyroidism: https://my.clevelandclinic.org/health/diseases/12120-hypothyroidism