Brown fat, also known as brown adipose tissue (BAT), is a unique type of fat in our bodies distinct from the white fat commonly found around the belly and thighs. Unlike white fat, which stores energy, brown fat burns calories from the foods we eat to generate heat, especially when exposed to cold temperatures, such as during winter swimming or cryotherapy. Recent research reveals that not only do newborns and small animals possess brown fat, but almost all adults also retain small amounts of it throughout their lives. This discovery opens new avenues for us to help clients achieve their health and fitness goals.

The Role of Brown Fat in Calorie Burning

Brown fat’s primary function is to convert calories into heat, a process known as thermogenesis. This characteristic makes it an exciting target for weight management and obesity treatment. Scientists are exploring ways to safely activate brown fat using drugs that enhance its heat-producing capabilities.

A study led by Professor Jan-Wilhelm Kornfeld from the University of Southern Denmark and Professor Dagmar Wachten from the University Hospital Bonn discovered a previously unknown mechanism within brown fat that limits its effectiveness. This mechanism, controlled by a protein called AC3-AT, switches off brown fat shortly after activation. By understanding and potentially blocking this “off switch,” new strategies can be developed to keep brown fat active for longer, thus boosting its calorie-burning potential.

Implications for Us

We can leverage these findings in several ways to benefit our clients:

  1. Educating Clients on the Benefits of Brown Fat Activation: Educate clients about the existence and benefits of brown fat. Explain how activities that promote brown fat activation, such as exposure to cold temperatures or specific exercise routines, can enhance their metabolic rate and aid in weight management.
  2. Incorporating Cold Exposure Techniques: Integrate cold exposure techniques into fitness programmes. This can include cold showers, ice baths, or outdoor exercises in colder climates. Cold exposure has been shown to activate brown fat, increasing the body’s ability to burn calories.
  3. Tailoring Nutrition Plans: Design nutrition plans that support brown fat activity. Some studies suggest that certain foods and nutrients, such as capsaicin found in chili peppers, can stimulate brown fat. Encourage clients to include these in their diets to maximise their metabolic rate.

Blocking the AC3-AT Protein

The study identified the protein AC3-AT as a key regulator that switches off brown fat after activation. In experiments with mice, those lacking the AC3-AT protein remained leaner and metabolically healthier despite a high-fat diet, compared to their counterparts with normal AC3-AT levels. This suggests that blocking AC3-AT could keep brown fat active, offering a potential treatment for obesity.

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Practical Applications

We can use this information to:

  • Advise Clients on Future Treatments: Stay informed about advancements in treatments that target AC3-AT. This knowledge can be shared with clients, especially those struggling with obesity, to keep them aware of emerging weight loss strategies.
  • Collaborate with Medical Professionals: Work alongside medical professionals to integrate new findings into comprehensive fitness and health plans. In our role, we are able to play a crucial role in monitoring and supporting clients who may participate in clinical trials or new treatment protocols involving brown fat activation.

The Broader Impact

Although brown fat tends to decrease with age, adults can still activate it through various methods, including cold exposure and certain physical activities. This activation can help stabilise weight loss, especially in conditions where calorie intake is high.

Additional Strategies

  • Developing Specialised Training Programmes: Create training programmes that incorporate elements known to activate brown fat. This can include high-intensity interval training (HIIT) combined with cold exposure, which may synergistically enhance calorie burning.
  • Personalising Client Goals: Use knowledge of brown fat activation to set realistic and personalised fitness goals for your clients. Understanding the science behind calorie burning can help us design effective weight management strategies.

Continued Research

The discovery of AC3-AT and other unknown proteins responding to cold exposure highlights the complex regulatory mechanisms of brown fat. Further research is needed to fully understand these mechanisms and their potential therapeutic impacts.

Our Role In Continued Research

  • Promote Awareness and Participation: Encourage clients to participate in research studies and clinical trials. We can be instrumental in recruiting and educating participants, thereby contributing to the advancement of scientific knowledge.
  • Integrate Research Findings: Stay updated with the latest research and integrate new findings into practice. This continuous learning approach ensures that we provide evidence-based guidance to our clients.

The understanding of brown fat and its role in calorie burning offers exciting opportunities. By incorporating knowledge about brown fat activation into our clients’ fitness programmes, nutrition plans, and education, we can enhance our clients’ metabolic health and support their weight management goals. As research progresses, staying informed and adaptable will be key to leveraging these insights for the benefit of clients.


Khani, S., Topel, H., Kardinal, R. et al. Cold-induced expression of a truncated adenylyl cyclase 3 acts as rheostat to brown fat function. Nat Metab 6, 1053–1075 (2024). Click here to review the full research article

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