TOFI (Thin Outside, Fat Inside)

 

Fat isn’t fat. Let me explain.

First of all I’m not talking about weight. I’m talking about adipose tissue. Adipose is a type of tissue in the body that stores energy in the form of fat.

There are 2 types of adipose tissue (fat):

• Brown fat 
• White fat

White fat is the most common type. It primarily serves as an energy reservoir and is found throughout the body, especially in the abdomen, thighs, buttocks, and arms.

Brown fat is energy burning fat. Unlike white fat, which stores energy, brown fat burns energy to produce heat. This helps the body maintain its core temperature, particularly in cold environments.

Brown fat is mainly found in newborns, and helps them regulate body temperature. In adults, Brown fat is present in smaller amounts, mostly in the neck, shoulders, and upper back.

In summary, white fat is energy-storing fat, and brown fat is energy burning fat.

But that’s not all. Now let’s talk about the types of white fat. We’re going deep. Stay with me.

There are 2 types of white fat:

• Subcutaneous fat
• Visceral fat

Subcutaneous fat is what we see. It is found just beneath the skin. It’s the fat you can pinch in areas like the belly, thighs, and arms. Subcutaneous fat is what we judge. It’s what we eyeball and use to refer to people as obese. But here’s the thing: It’s visceral fat that is the really evil fat.

Visceral fat is stored deep inside the abdomen. It surrounds internal organs like the liver, pancreas, and intestines. It is visceral fat and not subcutaneous fat that is associated with conditions like type 2 diabetes mellitus, insulin resistance, and cardiovascular disease. Excessive visceral fat is the real obesity.

Excessive amounts of subcutaneous fat can still contribute to health issues. And there exists a correlation between levels of subcutaneous fat and visceral fat, but this isn’t always the case.

TOFI stands for Thin Outside Fat Inside.

The term emerged in the late 2000s and is used to describe people who maintain a slim or normal-weight appearance while harboring dangerous levels of visceral fat.

It evolved from the term “metabolically-obese normal-weight (MONW)”. I think we can all agree TOFI rolls off the tongue much better than MONW (monwoo?).

Society has long equated thinness with health, believing that as long as someone isn't visibly overweight, they must be in good shape. This fixation on weight as the primary marker of health leaves many TOFI individuals unaware of their true metabolic risks. They may not feel the need to exercise regularly, monitor their diet, or get routine health screenings.

This false sense of security can delay diagnosis and intervention, allowing conditions like insulin resistance and cardiovascular disease to progress silently.

The use of Body Mass Index (BMI) only compounds the problem. BMI only considers height and weight. It fails to account for body composition and fat distribution. As a result, someone classified as “normal weight” by BMI standards could still have dangerously high levels of visceral fat.

So how can you know if you fail into the TOFI category? One of the simplest methods is measuring waist-to-hip ratio (WHR), which provides insight into central fat distribution.

WHR is calculated by dividing the waist measurement by the hip measurement

Generally, a WHR above 0.85 for women and above 0.90 for men is considered indicative of higher visceral fat levels and an increased risk for metabolic disorders, regardless of an individual’s outward appearance

WHR isn’t a perfect tool for diagnosing TOFI, but it can be a quick and accessible way to screen for the possibility of hidden metabolic risks. If someone has a normal BMI but a high WHR, it may indicate they need further evaluation with more precise methods.

Speaking of which…

More advanced tools, such as DEXA scans and MRI imaging, can accurately detect visceral fat levels. DEXA stands for Dual-Energy X-ray Absorptiometry (Big word, I know). It is one of the most precise methods for assessing body composition. It works by sending 2 different x-ray beams through your body and measuring how they get attenuated. A DEXA scan can distinguish between subcutaneous fat and visceral fat (as can an MRI).

So now we know how to find it, but what causes it in the first place. How can you be thin outside, yet “fat” inside. Unsurprisingly, it’s due to the usual suspects.

Diets high in processed foods, sugars, and unhealthy fats can contribute to fat deposition around internal organs, even in those who do not gain much visible weight.

A diet that lacks adequate protein intake can also contribute to TOFI. Protein is essential not only for muscle repair and growth but also for maintaining a healthy metabolic rate.

A lack of muscle mass is one of the characteristics of TOFI, as individuals with low muscle mass tend to have a slower metabolism, making it easier for them to accumulate fat around the internal organs. Visceral fat in particular thrives in an environment where muscle mass is low, as muscle helps to burn calories and regulate fat storage.

Without regular exercise, particularly strength training and aerobic activity, the body struggles to regulate fat distribution.

There also seems to be a genetic component to the presentation. Research suggests that a person’s genetic makeup can influence various aspects of fat storage, distribution, and metabolic processes.

Some people may have a genetic predisposition to store fat primarily in the visceral fat area (around organs), while others may store it in the subcutaneous fat area (under the skin).

Those with TOFI tend to accumulate fat in the abdominal region, even though their overall body weight may be within a normal range.

Genetics also affects how efficiently the body burns energy and metabolizes fat. Individuals with a genetic predisposition for TOFI may have a slower metabolism or an altered metabolic profile that leads to the accumulation of visceral fat.

Knowledge is power and knowing what causes TOFI can you combat and prevent it. Diet and exercise…you’ve got to change your life.

Regular physical activity is one of the most important changes anyone with TOFI can make. Specifically, focusing on both aerobic exercise and strength training can help reduce visceral fat, improve insulin sensitivity, and enhance overall metabolic function. 

You don’t need to become a gym bro. Aerobic exercises include: walking, running, swimming or cycling.

Avoid refined carbohydrates such as sugary snacks, sodas, white bread, and pastries, as these foods can cause blood sugar spikes and contribute to insulin resistance, promoting visceral fat storage.

Increase fiber intake by consuming more vegetables, fruits, legumes, and whole grains. Fiber slows down sugar absorption, helps regulate blood sugar levels, and contributes to fat loss, especially around the abdomen.

Prioritize protein to support muscle mass and prevent the loss of lean tissue. Include lean protein sources such as chicken, fish, eggs, tofu, and legumes in meals.

Personally, I believe in intermittent fasting. Intermittent fasting involves cycling between periods of eating and fasting, and research has shown that it can improve insulin sensitivity, reduce visceral fat, and help regulate metabolic processes.

There are several approaches you can use, such as the 16:8 method (fast for 16 hours and eat within an 8-hour window) or alternate-day fasting.

Before trying intermittent fasting, however, it's essential to consult a healthcare provider to ensure it is safe and appropriate for individual health needs.

A final piece of advice: Make it a habit to get regular health checks. These checks should include blood pressure checks, blood sugar assessments, and cholesterol tests.

We’re wrapping up. Let’s hit some key points

• TOFI refers to individuals who appear slim but have high levels of visceral fat.
• Visceral fat, which surrounds internal organs and is more dangerous than subcutaneous fat.
• Genetics, poor diet, physical inactivity, and low muscle mass contribute to the accumulation of visceral fat in people who appear thin.
• Many TOFI individuals are unaware of their condition due to society’s focus on weight as the primary health indicator, while metabolically healthy individuals with more visible fat often face stigmatization.
• TOFI can be detected through waist-to-hip ratio measurements or DEXA and MRI scans.
• Lifestyle changes like strength training, balanced eating, and stress management are key to improving metabolic health and reducing visceral fat.

By the way...there’s a third kind of fat. Beige fat. Beige is the color you get when you mix white and brown. So guess what Beige fat is…

While it is primarily classified as white fat, beige fat has the ability to "brown" in response to certain stimuli, such as cold exposure or physical activity.

Beige fat is still an area of active research, with scientists exploring how to leverage it for metabolic health and weight management.

I thought that was pretty cool so I wanted to share it.