Diets Debunked

TOFI and FOTI; strange acronyms, I know. What these refer to is different phenotypes of body composition; thin outside, fat inside, and fat outside, thin inside. The nuances with weight and health are very much demonstrated within these (rather crude) acronyms.

People who are TOFI, or “Thin Outside, Fat Inside,” appear thin but harbour a high proportion of both visceral and ectopic fat, which is the fat that surrounds our internal organs and the fat which can infiltrate them too. This hidden fat leads to metabolic issues despite a seemingly healthy outward appearance, and significantly predisposes them to insulin resistance, high blood lipids and heart disease.

Those who are FOTI, or “Fat Outside, Thin Inside,” refers to individuals who appear to be larger, and would be assumed to be at a higher risk of metabolic disease, but actually have a lower proportion of visceral fat. Instead, their fat is primarily subcutaneous, located just beneath the skin. This phenotype is often associated with a lower risk of metabolic complications compared to TOFI.

How TOFI and FOTI Impact Health

One of the primary indicators of how body composition will affect your health is not necessarily the amount of body fat you have, but rather, where you store it.

Storing body fat under the skin, or subcutaneously (as is common in FOTI phenotypes), is actually not generally associated with increased health risks. This fat is not considered detrimental to our metabolic health, unlike it’s more sinister cousins, visceral and ectopic fat.

Visceral fat is the fat that is in your abdomen, surrounding your organs. In our hunter-gatherer days, it was an evolutionary advantage; as visceral fat is a fat which is easy to add to and remove from, it provided quick and easily accessible energy for those days where you couldn’t find enough food. These days, however, when we have an abundance of calories within our world, it is a disadvantage. Those who are predisposed to put fat in their visceral stores are more likely to develop metabolic syndrome, even if they are naturally thin, a phenotype typically associated with reduced risk.

The same goes for ectopic fat. This is the fat that can streak through your organs, and often occurs once your visceral stores are full. This stuff is considered even more dangerous, due to it’s impact on metabolic health.

It’s these visceral and ectopic fat stores which give the most cause for concern. Therefore, those with the TOFI phenotypes are at greater risk for metabolic disease than those with FOTI phenotypes, even at a lower BMI, despite initial assumptions.

• TOFI: Individuals with the TOFI phenotype are at a higher risk of developing metabolic syndrome, type 2 diabetes, and cardiovascular diseases. The visceral fat in TOFI individuals can lead to insulin resistance, inflammation, and other metabolic disturbances, even if their Body Mass Index (BMI) is within the normal range.
• FOTI: While carrying excess weight can still pose health risks, individuals with the FOTI phenotype generally have a lower risk of metabolic complications. Subcutaneous fat is less metabolically active than visceral fat, meaning it has a lesser impact on insulin sensitivity and inflammation.

Diagnosing TOFI and FOTI

Diagnosing these phenotypes goes beyond simple BMI measurements. Here are some methods used to identify TOFI and FOTI:

1. Dual-Energy X-ray Absorptiometry (DEXA) Scans: These scans provide a detailed breakdown of body composition, including the distribution of fat and lean tissue.
2. Magnetic Resonance Imaging (MRI): MRI can offer precise measurements of visceral and subcutaneous fat.
3. Bioelectrical Impedance Analysis (BIA): This non-invasive method estimates body fat percentage and can give insights into fat distribution.
4. Blood Tests: Metabolic markers such as fasting glucose, insulin levels, and lipid profiles can provide additional clues about metabolic health.

Perhaps the easiest way to see if you’re at higher risk however, is taking a waist circumference measurement. This is taken just above your belly button, from the space about halfway between your rib cage and hip bones. This gives us an idea of the amount of fat you’re carrying round your middle. You can also compare this to your hips in what is known as the waist:hip ratio, where women should have a ratio of <0.85, and men <1.0.

What to Be Aware of If You Are TOFI or FOTI

If you identify as TOFI or FOTI, here are some key considerations:

• TOFI Individuals: Focus on reducing visceral fat through a balanced diet, regular exercise, and stress management. Regular check-ups with a healthcare provider can help monitor metabolic health. Ensure to be particularly mindful of the consumption of foods which can worsen metabolic factors, such as those which are high in saturated fat, sugar and salt.
• FOTI Individuals: While the risk of metabolic issues is lower, maintaining a healthy lifestyle is still crucial. Regular physical activity and a nutritious diet can help manage weight and overall health.

Understanding your body composition phenotype can provide valuable insights into your health risks and guide you towards making informed lifestyle choices. Whether you are TOFI or FOTI, being proactive about your health can make a significant difference in preventing chronic diseases and promoting well-being. Always consult with a healthcare professional for personalised advice tailored to your unique needs.

Stay informed, stay healthy, and embrace a lifestyle that nurtures your body from the inside out.