Not everyone who appears thin on the outside is also thin where it really matters -- on the inside. There is a word for this kind of people. The word is tofi and it stands for thin on the outside, fat on the inside. The Guardianreports that internal fat has been linked to serious health risks including diabetes and heart disease. Thanks to MRIs doctors are now able to determine whether or not people carry too much internal fat.
Bell has spent years studying how human beings store and use their adipose tissue, or fat. He has carried out studies showing that people who would be considered slim can have large quantities of fat within them.
'This is particularly true of men who have a slim build but who do little or no exercise,' he said. 'We know now that 40 per cent of people have fat infiltration of the liver, which is linked to so many other health problems.'
He said of Schwartz: 'He is slim, he's not overweight, but you can see there are some areas where there is a bit of a build-up of visceral fat. He doesn't have a lot of subcutaneous fat [the kind that lies just under the skin], but I can see there is quite a bit around the organs and some in the muscle.'
Thanks to this new technique, Bell and others are able to understand why appearances can be so deceptive. Someone like Schwartz, who is young, falls into the category of those who need to start changing their lifestyle. Unknowingly, he is on the way to becoming what is jokingly described as a 'Tofi' - Thin on the Outside, Fat on the Inside. Tofis probably need to worry more about their health than others, because the fat deposits they carry are hidden in the white fat that lies around their vital organs, streaked through their underused muscles, and wrapped around the heart. It is this fat that sends out the chemical signals which eventually lead to insulin resistance, diabetes and heart conditions, rather than the fat lying in dimples underneath the skin.
The findings about Tofis throughs out the useless BMI factor that has sidetracked many physicians. The study looked at Sumo wrestlers who have a very high BMI but very little internal fat.
What really counts, says Bell, is how and where the body's energy supply is stored. Fat cells are extremely intelligent - 'versatile players', as the American obesity specialist Roger Unger called them - which hang on stubbornly even through crash diets. For years, doctors saw fat tissue as a kind of passive storage compartment, but new research has shown that the fat cells, or adipocytes, are dynamic beings.
In Japan, sumo wrestlers have been put through MRI scanners to look at their fat composition. Even though they have a BMI of 56 and are eating up to 5,000 calories a day, they have very little internal fat. 'They have low cholesterol, they have low insulin resistance and a low level of triglycerides [fatty acids],' said Bell. 'Their fat is all stored under the skin, on the outside.'
The bottom line is you need information about a person's internal and external fat before you can make any kind of judgement about how healthy they are.