Lose weight by freezing? The new weight loss strategy

⏱ 9 min read

The days are getting shorter, temperatures are dropping and everyone is talking about winter fat again. On the one hand, this may be due to the hearty meals suitable for cold days, but also to the fact that we overlook the odd lifebelt under our mountains of clothes until it's time to head back to the beach. Van Marken Lichtenbelt from Maastricht University describes another component in Trends in Endocrinology and Metabolism: The heating.

Freezing helps you lose weight

By now, every child knows that if you want to lose weight, you either have to eat fewer calories or burn more calories through physical activity. The keyword is: negative energy balance and is usually a thorn in the side of anyone who wants to lose weight. But energy consumption can also be boosted without physical exertion - by freezing! But you don't have to shiver to do this - even 18 to 19 degrees Celsius increases energy consumption significantly. Where a lot helps, more helps better, as a study from Japan confirms: staying in a room at temperatures of 17 degrees Celsius for just 2 hours a day resulted in a reduction in fat tissue after just 6 weeks. The body should get used to the new, cold environment very quickly, according to van Marken Lichtenbelt. For this reason, temperature training at 15 degrees Celsius should be carried out for six hours a day, whereby the body should become accustomed to the cold within 10 days. Room temperatures of 18 to 19 degrees Celsius then become easily bearable and the pounds can tumble off. Although the approach might appeal to many a sports fanatic, its feasibility remains questionable. At the latest when it is introduced in offices, one would certainly be confronted with protests...

How does cold burn calories? Brown fat explained

The body keeps its core temperature stable. When the surroundings get cooler, it has to produce more heat, and heat costs energy. A large part of this heat comes from brown fat, also called brown adipose tissue. White fat stores excess energy. Brown fat does the opposite: it burns fat to produce heat when the body is exposed to cold (Yoneshiro et al., 2013).

For a long time, brown fat was thought to matter only in small mammals and babies. Then researchers found it in adults. In a study with 24 healthy men, brown fat was active in 23 of them during mild cold of 16 degrees Celsius, but not at a comfortable 22 degrees (van Marken Lichtenbelt et al., 2009). An analysis of body scans from 1,972 patients located the brown fat in a region from the front of the neck to the chest. Women had it more than twice as often as men, and people with more brown fat had a lower body mass index, especially at an older age (Cypess et al., 2009).

How much energy does this use? A meta-analysis of ten randomized controlled trials compared people in mild cold of 16 to 19 degrees with people at a room temperature of 24 degrees. In the cold, energy expenditure was about 188 kcal a day higher, and both the volume and the activity of brown fat increased (Huo et al., 2022).

Cold raises energy expenditure from the outside. From the inside, the metabolism needs nutrients to turn food into energy. The eight B vitamins act as coenzymes in a vast number of metabolic reactions in the cells, energy production among them (Kennedy, 2016). The Metabolism Package Plus from Herbano contains a vitamin B complex with all eight B vitamins and four more products for the metabolism.

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How cold and for how long? What the studies show

None of the studies used ice baths. They all worked with mild cold between 14 and 19 degrees Celsius, which is the temperature of a cool room. The table shows the most important studies at a glance.

The Japanese study is the one mentioned above. Its participants were healthy people with little active brown fat. A single stay of two hours at 19 degrees already increased their energy expenditure. After six weeks with two hours a day at 17 degrees, their brown fat was more active and their body fat mass had gone down. The more the brown fat activity rose, the more body fat was lost. Brown fat can therefore be built up even in people who have little of it (Yoneshiro et al., 2013).

The body also gets used to the cold quickly. After a cold acclimation of ten days, brown fat was more active and the body produced more heat without shivering. The participants judged the same cold environment as warmer, felt more comfortable in it and shivered less. The researchers concluded that a variable indoor climate with frequent cold exposures might be an acceptable and economic way to increase energy expenditure (van der Lans et al., 2013).

Cold does more than burn calories: benefits for blood sugar

Cold training also improves how the body handles sugar. In eight people with type 2 diabetes, ten days of cold acclimation at 14 to 15 degrees Celsius increased insulin sensitivity by about 43% (Hanssen et al., 2015). In another study, five healthy men slept in a room at 19 degrees for one month. Their brown fat increased, and their insulin sensitivity after meals improved (Lee et al., 2014).

Brown fat is linked to better health in general. In an analysis of 52,487 patients, people with brown fat had type 2 diabetes, abnormal blood lipids, coronary artery disease, heart failure and high blood pressure less often. Their blood sugar, triglyceride and HDL cholesterol values were better as well. The benefit was most pronounced in people with overweight or obesity (Becher et al., 2021).

Cold training in everyday life: how to get started

You do not need a laboratory for this. A cooler everyday life is enough:

• Turn the heating down: Room temperatures of 18 to 19 degrees Celsius already increase energy expenditure. Lower the thermostat step by step until you reach this range.
• Sleep in a cool bedroom: In the study mentioned above, one month of nights at 19 degrees was enough to increase brown fat.
• Give your body ten days: The first days feel chilly. After about ten days the body has adapted, the same temperature feels warmer and you shiver less.
• Cool, but without shivering: You do not have to shiver. Brown fat produces heat without shivering, and mild cold is enough to activate it.
• Stay with it: Brown fat adapts to its surroundings. It increases in mild cold and decreases again in warmth (Lee et al., 2014). Regular cold exposure therefore counts more than a single cold day.

If you have diabetes, heart disease or high blood pressure, talk to your doctor before you start cold training.

Nutrients for an active metabolism

A cool room raises energy expenditure. A strong metabolism makes sure that the body turns calories and nutrients into usable energy. The Metabolism Package Plus from Herbano combines five products that support the metabolism from different sides:

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• Probiotics Forte Plus: for a healthy and optimized intestinal flora
• Calcium Magnesium Plus: for more energy and fewer hunger pangs
• Vitamin B Complex Forte: all eight B vitamins for effective fat burning
• MSM: for a balanced blood sugar level

The package stimulates the entire metabolism in a healthy and sustainable way, which makes it a good partner for a cooler everyday life.

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Fat freezing at the clinic: what is cryolipolysis?

Fat freezing, known medically as cryolipolysis, uses cold in a different way. It is a non-invasive cosmetic treatment that reduces the fat under the skin in one area through controlled cooling. Studies have covered the abdomen, flanks, thighs, the area under the chin, arms, back and chest (Bernstein, 2016).

The results are well documented. A meta-analysis of 30 studies with 3,158 participants compared the values 12 weeks after the treatment with the starting values. Abdominal circumference was 3.56 cm smaller on average, the body mass index was 1.80 points lower, and 80.4% of the patients were satisfied (Ravindran et al., 2025). In a systematic review of 19 studies, the treated fat layer became 14.67 to 28.5% thinner when measured with a caliper and 10.3 to 25.5% thinner when measured by ultrasound (Ingargiola et al., 2015).

Side effects are common, but minor. In the meta-analysis, 49.5% of the patients reported numbness, 44.5% redness, 30.5% swelling and 28.8% pain (Ravindran et al., 2025). A rare complication is paradoxical adipose hyperplasia. Here the fat in the treated area grows instead of shrinking. In a meta-analysis of 28 studies with 13,078 patients, this happened in 0.22% of cases, which is about 1 in 455 patients (Mah et al., 2025).

Both methods use cold, but they do different things. Fat freezing shapes single fat deposits in a clinic. A cooler everyday life raises the energy expenditure of the whole body, activates brown fat and costs nothing.

Frequently asked questions

What are the benefits of slimming by freezing?

Mild cold raises energy expenditure without any physical exertion: at 16 to 19 degrees Celsius, the body uses about 188 kcal more a day than at 24 degrees. With regular cold exposure, brown fat becomes more active and body fat mass goes down. In people with type 2 diabetes, ten days of cold acclimation also increased insulin sensitivity by about 43%.

Does fat freezing really work on belly fat?

Yes. In a meta-analysis of 30 studies, abdominal circumference was 3.56 cm smaller on average 12 weeks after cryolipolysis. A cool room works on body fat as well: in a Japanese study, two hours a day at 17 degrees reduced body fat mass within six weeks.

When will I see results?

With a cooler everyday life, the body gets used to the cold within about ten days. A reduction in body fat was measured after six weeks of daily cold exposure. After fat freezing at a clinic, the studies measured the results 12 weeks after the treatment.

Are the results permanent?

Brown fat adapts to its surroundings: one month of cool nights increased it, and one month of warm nights reduced it again. A cooler everyday life should therefore become a habit. After fat freezing, two documented cases still showed the result 6 and 9 years after the treatment.

Why is my belly bigger after fat freezing?

Swelling is common shortly after the treatment and was reported by 30.5% of patients. In rare cases, the fat in the treated area grows instead of shrinking, which doctors call paradoxical adipose hyperplasia. It occurred in 0.22% of 13,078 patients, which is about 1 in 455 patients. If the treated area becomes larger, have it examined by a doctor.

Sources (in English):

Lichtenbelt, W. v. M., Kingma, B., van der Lans, A.,& Schellen, L. (2014). Cold exposure - an approach to increasing energy expenditure in humans. Trends in Endocrinology and Metabolism, 25(4):165-7, doi: 10.1016/j.tem.2014.01.001

Van Marken Lichtenbelt, W. D., Vanhommerig, J. W., Smulders, N. M., Drossaerts, J., Kemerink, G. J., Bouvy, N. D. et al. (2009, April). Cold-Activated Brown Adipose Tissue in Healthy Men. The New England Journal of Medicine, 360:1500-1508, doi: DOI: 10.1056/NEJMoa0808718 

Yoneshiro, T., Aita, S., Matsushita, M., Kayahara, T., Kameya, T., Kawai, Y., Iwanaga, T., & Saito, M. (2013). Recruited brown adipose tissue as an antiobesity agent in humans. The Journal of Clinical Investigation, 123(8):3404-3408, doi: 10.1172/JCI67803

van der Lans, A. A., Hoeks, J., Brans, B., Vijgen, G. H., Visser, M. G., Vosselman, M. J. et al. (2013). Cold acclimation recruits human brown fat and increases nonshivering thermogenesis. The Journal of Clinical Investigation, 123(8):3395-3403, doi: 10.1172/JCI68993

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, doi: 10.3389/fphys.2022.917084

Cypess, A. M., Lehman, S., Williams, G., Tal, I., Rodman, D., Goldfine, A. B. et al. (2009). Identification and importance of brown adipose tissue in adult humans. The New England Journal of Medicine, 360(15):1509-1517, doi: 10.1056/NEJMoa0810780

Hanssen, M. J., Hoeks, J., Brans, B., van der Lans, A. A., Schaart, G., van den Driessche, J. J. et al. (2015). Short-term cold acclimation improves insulin sensitivity in patients with type 2 diabetes mellitus. Nature Medicine, 21(8):863-865, doi: 10.1038/nm.3891

Lee, P., Smith, S., Linderman, J., Courville, A. B., Brychta, R. J., Dieckmann, W. et al. (2014). Temperature-acclimated brown adipose tissue modulates insulin sensitivity in humans. Diabetes, 63(11):3686-3698, doi: 10.2337/db14-0513

Becher, T., Palanisamy, S., Kramer, D. J., Eljalby, M., Marx, S. J., Wibmer, A. G. et al. (2021). Brown adipose tissue is associated with cardiometabolic health. Nature Medicine, 27(1):58-65, doi: 10.1038/s41591-020-1126-7

Kennedy, D. O. (2016). B Vitamins and the Brain: Mechanisms, Dose and Efficacy – A Review. Nutrients, 8(2):68, doi: 10.3390/nu8020068

Ravindran, R., Pizzol, D., Rahmati, M., Caminada, S., Yon, D. K., Shin, J. I. et al. (2025). Cryolipolysis and associated health outcomes, adverse events, and satisfaction: A systematic review and meta-analysis. Obesity Reviews, 26(8):e13925, doi: 10.1111/obr.13925

Ingargiola, M. J., Motakef, S., Chung, M. T., Vasconez, H. C., & Sasaki, G. H. (2015). Cryolipolysis for fat reduction and body contouring: safety and efficacy of current treatment paradigms. Plastic and Reconstructive Surgery, 135(6):1581-1590, doi: 10.1097/PRS.0000000000001236

Mah, A. E., Razeghi, P., Li, C., Datta, S., Tao, B. K., Ahmad, J., & Austin, R. E. (2025). Incidence of Paradoxical Adipose Hyperplasia After Cryolipolysis: A Systematic Review and Meta-Analysis. Aesthetic Surgery Journal Open Forum, 7:ojaf142, doi: 10.1093/asjof/ojaf142

Bernstein, E. F. (2016). Long-term efficacy follow-up on two cryolipolysis case studies: 6 and 9 years post-treatment. Journal of Cosmetic Dermatology, 15(4):561-564, doi: 10.1111/jocd.12238