Introduction:
Many ice bath companies and wellness enthusiasts have made strong claims stating how ice baths can help you lose fat by simply taking a plunge. However, the studies show that Ice baths increase metabolism* through a process called thermogenesis*, and that the evidence supporting ice baths as a tool for fat loss is far from clear cut. By the end of this blog post you should have a greater understanding of whether ice baths are an efficient means of fat loss* or not.
Glossary:
Thermogenesis: the process where the body converts glucose and fat into heat energy.
Hypothalamus: the area of the brain responsible for regulating temperature.
Metabolism: all the chemical reactions that occur in the body to produce energy and genetic material.
Fat Loss: a reduction in the total volume of fat tissue on an individuals body.
Types of Fat Tissue:
Before we get into the nitty gritty, we must first understand the different types of fat our body can produce,
Brown Fat- this is most present in infancy and declines with age. The main function is to generate heat through non-shivering thermogenesis which it can do as unlike white fat it contains mitochondria which also give it the brown colour. This is commonly referred to as the ‘healthy fat’.
White Fat – Makes up the majority of fat tissue in our body. It is used to store energy, act as insulation against harsh temperatures and protect soft organs from damage. White fat tissue also helps to secrete hormones that regulate hunger, metabolism and inflammatory response.
Beige Fat – is a combination of both white and brown fat and usually occurs as a result of stimuli such as cold exposure. It can be used for both energy storage and to be metabolised to create heat energy.
The Science Behind Ice Baths and Metabolism:
When exposed to the cold, thermoreceptors on the skin will detect a sudden drop in temperature and send a signal to the hypothalamus* in the brain (Tan & Knight, 2018). The hypothalamus will then respond in two ways, one, by sending a signal to the muscles to begin rapidly contracting and relaxing and two, by stimulating the thyroid gland to release adrenaline and epinephrine.
Rapid contraction of the muscles will cause a sudden increase in metabolism through a process called shivering thermogenesis. This is where the body metabolises glucose and fat tissue into energy for the muscles to contract and heat is produced as a by-product (Lee et al, 2014). Shivering thermogenesis is only a short term response to cold exposure usually only lasting 1-3 minutes as your body can fatigue rapidly during this process and is done to allow for an immediate boost in heat.
The release of adrenaline and epinephrine will cause a gradual increase in metabolism through non-shivering thermogenesis. This is where brown fat is activated to be converted into heat energy (Lee et al, 2014). Non-shivering thermogenesis is a more efficient and longer lasting method of your body maintaining its temperature and occurs when exposed to the cold for longer periods of time.
Short Term Impact on Fat Loss:
Both shivering and nonshivering thermogenesis will burn fat calories for heat energy in the short term. This is typically 188 calories from 10 minutes of cold exposure (Huo et al, 2022) . However, not all of these calories will be from fat tissue with many of them coming from glucose, and in order to lose fat tissue you must be in a substantial calorie deficit. A calorie deficit is where you are consuming less calories than you are using forcing your body to draw on energy from your fat reserves.
Ice baths as a sole treatment for fat loss will not lead to any substantial change in the short term. This is because if you were in a calorie deficit of 188 calories it would take a minimum of 40 days to lose 1kg of fat as 1kg of fat contains 7700 calories. However, ice baths could be used as an adjunct treatment for fat loss on top of other methods such as exercise and diet to push you into a further calorie deficit.
Long Term Impact on Fat Loss:
Long term cold exposure has been shown to change your body’s fat composition but not have any significant impact on total amount of fat loss (Huo et al, 2022). The changes to fat composition are an increase in brown fat tissue and decrease in white fat tissue due to it being converted into beige fat, as well as more fat tissue being distributed around the muscles rather than the main organs. This is beneficial as excess fat around internal organs is associated with high blood pressure, heart disease and some cancers.
Additionally, studies have highlighted that long term cold exposure often leads to an increased appetite (Huo et al, 2022). This is likely why there has been no evidence found to support ice baths leading to fat loss as people are likely eating extra calories to make up for any loss whilst in the ice bath. Worse still, some individuals may find they gain weight as 188 calories is not that difficult to consume.
Benefits of Increased Brown Fat:
Higher levels of brown fat lead to improved metabolic health. This is as brown fat leads to a decrease in insulin resistance and an increase in insulin sensitivity which is associated with a reduced risk of developing type 2 diabetes (Søberg et al, 2021).
Additionally higher levels of brown fat tissue have been found to directly correlate with a lower risk of developing cardiovascular related diseases such as a heart attack (Raiko et al, 2020). This is because brown fat tissue helps to maintain lower levels of glucose and fat levels in the bloodstream by using them to create heat energy. This will help to maintain blood vessel health by keeping cholesterol and blood pressure levels lower.
It has also been suggested that those with higher levels of brown fat burn more calories on a daily basis compared to those with more white fat, this is because there are more calories available to burn due to brown fat being able to be converted into heat energy. However, the evidence for this is limited.
Limitations of Ice Baths as a Fat Loss Tool:
While there is evidence to show that ice baths and other types of cold exposure increase metabolism and improve overall metabolic health. There is little evidence to suggest that this leads to any long term fat loss and rather leads to a change in fat composition by increasing the amount of brown and beige fat tissue.
Potential Downsides:
Weight gain: Due to frequent cold exposure over a prolonged period causing increased appetite this could cause you to eat in excess of the calories you burnt whilst in the ice bath resulting in weight gain.
Affordability: ice baths are not the most affordable way to lose weight with exercise and diet being two free ways which are highly effective at leading to fat loss. A combination of both diet and exercise is best. With diet helping you to specifically manage how many calories you are consuming and exercise helping you to burn more calories making it easier to be in a deficit. Running is an example of great calorie burning exercise with you burning 100 calories for every mile you run.
Tips for an Effective Diet:
1. Consume fewer calories than you are eating.
2. Count every calorie including juices, sauces and oils.
3. Ensure your diet is sustainable by choosing foods that are healthy but that you also enjoy.
4. Have a high protein intake as protein based foods are more filling and will help to maintain muscle mass. Muscle mass is vital to sustain good metabolic health as it plays a key role in managing glucose levels in your blood.
5. Eat plenty of high fibres foods as similar to protein they are generally low calorie and more filling alternatives to carbohydrates and sugars.
6. Always ensure you are eating a safe amount of calories.
Conclusion:
For the majority, ice baths are not an efficient tool to help you lose fat but they will change the composition of the fat in your body so you have more healthy brown fat tissue. Alternatively, if you are someone who actively counts calories and is heavily focused on fitness and conditioning, ice baths can contribute to healthy fat loss. Ice baths can help to improve your metabolic health and reduce your chance of getting conditions such as type 2 diabetes. Taking cold water plunges are more effective at improving recovery and boosting mental health, so if you are looking to lose fat, try exercising regularly and focusing on a nutritional diet as these are the most effective methods.
Reference List:
- Tan, C. & Knight, Z. (2018). Regulation of Body Temperature by the Nervous System. Neuron, 98(1), 31-48. https://www.sciencedirect.com/science/article/pii/S0896627318301430
- Lee, P., Smith, S., Linderman, J., Courville, A. B., Brychta, R. J., Dieckmann, W., Werner, C. D., Chen, K. Y., & Celi, F. S. (2014). Temperature-acclimated brown adipose tissue modulates insulin sensitivity in humans. Diabetes, 63(11), 3686–3698.
https://doi.org/10.2337/db14-0513 - Huo, C., Song, Z., Yin, J., Zhu, Y., Miao, X., Qian, H., Wang, J., Ye, L., & Zhou, L. (2022). Effect of Acute Cold Exposure on Energy Metabolism and Activity of Brown Adipose Tissue in Humans: A Systematic Review and Meta-Analysis. Frontiers in physiology, 13, 917084. https://doi.org/10.3389/fphys.2022.917084
- Søberg, S., Löfgren, J., Philipsen, F. E., Jensen, M., Hansen, A. E., Ahrens, E., Nystrup, K. B., Nielsen, R. D., Sølling, C., Wedell-Neergaard, A. S., Berntsen, M., Loft, A., Kjær, A., Gerhart-Hines, Z., Johannesen, H. H., Pedersen, B. K., Karstoft, K., & Scheele, C. (2021). Altered brown fat thermoregulation and enhanced cold-induced thermogenesis in young, healthy, winter-swimming men. Cell reports. Medicine, 2(10), 100408. https://doi.org/10.1016/j.xcrm.2021.100408
- Raiko, J., Orava, J., Savisto, N., & Virtanen, K. A. (2020). High Brown Fat Activity Correlates With Cardiovascular Risk Factor Levels Cross-Sectionally and Subclinical Atherosclerosis at 5-Year Follow-Up. Arteriosclerosis, thrombosis, and vascular biology, 40(5), 1289–1295. https://doi.org/10.1161/ATVBAHA.119.313806
FAQ’s:
Ice baths burn on average 188 calories per 10 minutes spent inside the cold bath. However, this has not been proven to lead to any fat or weight loss long term due to frequent long term use of ice baths leading to increased appetite. This increased appetite will cause people to no longer be in a calorie deficit as they will consume all the calories they burn off in the ice bath.
No ice baths cannot reduce belly fat. Instead, frequent ice baths will change your fat composition to increase the amount of healthy brown fat you have and decrease the amount of white fat you have. Higher levels of brown fat leads to lower levels of insulin resistance and higher insulin sensitivity which is associated with a reduced risk of type 2 diabetes.
The most effective fat loss treatment is exercise and diet. This is because diet will allow you to restrict your caloric intake so that you can be in a deficit. A calorie deficit will force your body to draw on fat reserves for energy leading to the breakdown of fat tissue. Exercise will further push you into a calorie deficit as it will increase your total energy expenditure for the day. For example on average for every mile run 100 calories is burnt.
White fat tissue is used to store energy, protect your vital organs from damage and insulate against harsh temperatures. Whereas brown fat is used for heat energy through a process called non-shivering thermogenesis. Frequent cold exposure aims to increase your amount of brown fat and decrease the amount of white fat. This is because whilst you need both types of fat to survive too much white fat can lead to excess inflammation in the body leading to conditions like heart disease.
