Obesity and Type 2 Diabetes have reached pandemic proportions in their reach and pervasiveness, leaving few populations across the globe untouched.1 In this article I will talk about a possible use of cold temperatures in the maintenance or reduction of body weight and perhaps the improvement of our lipid profiles and blood glucose levels. 2–4
Types of Fat
Mammals, including humans have two types of fat in their bodies – White Adipose Tissue (WAT) and Brown Adipose Tissue (BAT). Simply put, WAT accumulates surplus energy and BAT dissipates energy directly as heat.
WAT is distributed throughout the body; it can be found below the skin and centrally located, around our organs. The first is called subcutaneous fat and the second, visceral fat. Visceral fat is not considered beneficial and is associated with many health issues. BAT has been found in the neck, upper neck, chest and between the shoulder blades.5
Brown Adipose Tissue (BAT) is a thermogenic (that which creates heat) organ that is involved in energy expenditure, as opposed to white fat, which stores excess energy. BAT appears to be activated via exposure to cold temperatures.
Upon activation, BAT consumes substantial amounts of glucose and fatty acids (mainly triglycerides) as fuel for thermogenesis.
Body Temperature Regulation
Our bodies want to stay at a certain temperature. When we’re exposed to cold, one of two things usually happen as mechanisms to preserve our core temperature:
- Our blood flow patterns change in order to decrease heat loss
- Our energy expenditure is increased manifold above the usual Resting Energy Expenditure (REE) to be used to counter balance heat lost. This is called Cold Induced Thermogenesis (CIT).
CIT can also be defined as the adaptive component of REE, that increases REE in the presence of colder temperatures, to help maintain a stable and desirable core body temperature.
Types of CIT
CIT can be divided into two types:
- Shivering thermogenesis and
- Non-shivering thermogenesis
Shivering thermogenesis increases heat production in the body through muscular contractions. This causes the REE to increase up to 5 times. This process is uncomfortable and fatiguing, in addition to impacting our ability to effectively use our motor skills. Shivering is complex is nature, and therefore it is difficult to identify its onset and regulation, though this source places the onset of shivering at about 2 degrees Celsius in adults, with onset in older people one degree higher.
Non-shivering thermogenesis is triggered by mild cold and can increase REE by up to 30%, without the discomforts of shivering thermogenesis. This makes it an attractive intervention for targets such as obesity and related comorbidities. Brown Adipose Tissue (BAT) plays a key role in non-shivering thermogenesis.
Interestingly, a higher level of body fat has a blunting effect on CIT perhaps due to the increased effect of insulation. So, the more fat we have on our bodies, the lower the effect of CIT on our REE / metabolic burn rate. Conversely, the leaner we are the more the effect of CIT on our REE. Additionally, there is an apparent correlation between CIT and BAT volume / activity. Also, it may be possible to increase BAT abundance through chronic exposure to cold environments.
A point to note is that the most profound physiological changes happen in the first 30 minutes to cold exposure.
Effects on Weight
Ultimately, when our bodies have more energy than they need, we gain weight, and when they have less energy than they need, we lose weight. Of the total energy expenditure, our REE constitutes a major chunk of it (50-80%), so even small changes in REE, if not compensated by food intake can have significant effects on body weight.
Finally, the answer to the title question, does exposure to cold aid in weight loss. My interpretation of the data is that chronic exposure to uncomfortable though non-hazardous cold temperatures may be an interesting intervention to increase overall discipline and health, the outcomes of which can include beneficial effects on our weight, blood glucose and lipid profiles.
- 1.Unnikrishnan R, Pradeepa R, Joshi S, Mohan V. Type 2 Diabetes: Demystifying the Global Epidemic. Diabetes. 2017;66(6):1432-1442. doi:10.2337/db16-0766
- 2.Peres V, Hernández-Saavedra D, White J, Stanford K. Cold and Exercise: Therapeutic Tools to Activate Brown Adipose Tissue and Combat Obesity. Biology (Basel). 2019;8(1). doi:10.3390/biology8010009
- 3.Acosta F, Martinez-Tellez B, Sanchez-Delgado G, et al. Physiological responses to acute cold exposure in young lean men. PLoS One. 2018;13(5):e0196543. doi:10.1371/journal.pone.0196543
- 4.Brychta R, Chen K. Cold-induced thermogenesis in humans. Eur J Clin Nutr. 2017;71(3):345-352. doi:10.1038/ejcn.2016.223
- 5.Gil A, Olza J, Gil-Campos M, Gomez-Llorente C, Aguilera CM. Is adipose tissue metabolically different at different sites? Int J Pediatr Obes. Published online September 2011:13-20. doi:10.3109/17477166.2011.604326