Understanding the role of subcutaneous fat
Subcutaneous fat is the layer of fat located just beneath the skin. It makes up approximately 90% of a person's total body fat. Unlike visceral fat, which surrounds internal organs and is considered more metabolically dangerous, subcutaneous fat has historically been viewed as less of a health threat. However, this perspective has evolved. While excessive subcutaneous fat is a factor in obesity, having too little is also problematic, as this layer is crucial for several biological processes.
Its key functions include providing a protective cushion for the body, storing energy for later use, regulating body temperature, and playing a role in hormone production. An insufficient amount of this vital fat can compromise these functions, leading to systemic issues throughout the body.
The crucial difference: Subcutaneous vs. visceral fat
While both types of fat contribute to total body fat percentage, their location and metabolic activity differentiate their impact on health. Visceral fat is situated deep within the abdominal cavity, surrounding the major organs. It is more metabolically active than subcutaneous fat, producing inflammatory substances that can lead to serious health problems, such as type 2 diabetes and cardiovascular disease.
Subcutaneous fat, by contrast, lies just under the skin. It serves as an energy reserve and shock absorber. The key health risk from low subcutaneous fat is primarily linked to an overall low body fat percentage, which can disrupt normal bodily functions rather than producing the same inflammatory responses as high visceral fat. In some cases, low subcutaneous fat can occur alongside high visceral fat, creating a particularly high-risk body composition.
Comparing subcutaneous and visceral fat
| Feature | Subcutaneous Fat | Visceral Fat |
|---|---|---|
| Location | Just beneath the skin. | Deep within the abdominal cavity, surrounding organs. |
| Health Risk | Low levels can cause systemic issues. Excessive levels contribute to obesity but are less metabolically active than visceral fat. | Higher risk of serious health conditions like type 2 diabetes, heart disease, and stroke. |
| Metabolic Activity | Less metabolically active. | Highly metabolically active, producing inflammatory proteins. |
| Physical Feel | Can be pinched or felt just under the skin. | Cannot be pinched; located too deep. |
| Risk Factor | Low amounts can be a risk factor for unfavorable glucose and lipid levels. | High amounts are a significant risk factor for cardiometabolic diseases. |
What happens when subcutaneous fat is too low?
When body fat, including the subcutaneous layer, drops below a healthy threshold, the body's essential functions can be severely impacted. The risks are varied and can affect multiple bodily systems:
- Weakened immune system: Fat is vital for immune function, and low levels can make a person more susceptible to illness and infection.
- Hormonal imbalances: Body fat is essential for hormone production, including the sex hormones estrogen and testosterone. For women, this can lead to irregular menstrual cycles or amenorrhea (absence of menstruation), and in men, lower testosterone levels.
- Nutrient deficiencies: Many key vitamins, such as A, D, E, and K, are fat-soluble, meaning they require fat for absorption. A lack of dietary fat can lead to deficiencies in these vitamins, impacting vision, immune function, and bone health.
- Poor body temperature regulation: The subcutaneous fat layer acts as an insulator, helping to maintain body temperature. With insufficient fat, individuals may feel perpetually cold.
- Low bone density: In women, hormonal disruption from low body fat can cause decreased bone density, increasing the risk of osteoporosis.
- Fatigue and weakness: Fat is the body's primary long-term energy store. Without adequate reserves, individuals can experience chronic fatigue and muscle weakness.
- Mental health issues: The psychological pressure to maintain a dangerously low body fat percentage can lead to anxiety, depression, body dysmorphia, and other eating disorders.
Causes and treatment for low subcutaneous fat
Low subcutaneous fat can result from several factors, including genetics, medical conditions, and lifestyle choices. Genetic predispositions can influence where fat is stored, while certain conditions, like some forms of lipodystrophy or inflammatory diseases, can cause fat loss. Lifestyle factors often include extremely restrictive diets, excessive cardiovascular exercise, and eating disorders.
Treatment begins with addressing the underlying cause. A medical professional can help diagnose any health conditions or eating disorders. For those with low body fat due to lifestyle, the focus shifts to healthy weight gain. This includes consuming a sufficient number of calories to create a surplus, with an emphasis on nutrient-dense foods and healthy fats.
Lifestyle adjustments to increase healthy fat levels
- Balanced, calorie-sufficient diet: Incorporate healthy sources of fats such as avocados, nuts, seeds, and fatty fish. Ensure a consistent calorie surplus to promote weight gain.
- Prioritize strength training: While cardio burns calories, strength training helps build muscle mass, which can support overall healthy weight gain.
- Manage stress and sleep: High stress levels can negatively impact weight regulation. Adequate, restful sleep is also crucial for hormone balance and appetite control.
- Consult a professional: Work with a registered dietitian or nutritionist to develop a safe and effective dietary plan tailored to your needs. For individuals with very low body fat, especially athletes, this is crucial for long-term health.
Conclusion: Seeking a healthy balance
While society often focuses on reducing fat, maintaining an adequate level of subcutaneous fat is vital for overall health. The goal should not be to minimize body fat to the lowest possible percentage but to achieve a healthy body composition that supports all bodily functions. Low subcutaneous fat is a red flag that should be taken seriously, as it can indicate underlying health issues or lead to serious complications. By understanding the role of fat in the body and working towards a healthy balance through diet, exercise, and lifestyle, individuals can ensure their well-being is prioritized over aesthetic extremes.
For a deeper understanding of body composition and its impact on health, you can consult resources like the American Journal of Clinical Nutrition.
