TOFI — Mediated Wiki

{{Short description|Individual with disproportionate amount of fat}} thumb|upright=1.3|MRI image of a TOFI man and a normal control '''TOFI'''<ref>{{Cite journal | last1 = Thomas | first1 = E. Louise| last2 = Frost | first2 = Gary| last3 = Taylor-Robinson | first3 = Simon D.| last4 = Bell | first4 = Jimmy D.| title = Excess body fat in obese and normal-weight subjects | doi = 10.1017/S0954422412000054 | journal = Nutrition Research Reviews| volume = 25 | issue = 1 | pages = 150–161 | year = 2012 | pmid = 22625426 | doi-access = free }}</ref><ref>{{Cite journal | last1 = Thomas | first1 = E. Louise| last2 = Parkinson | first2 = James R.| last3 = Frost | first3 = Gary S.| last4 = Goldstone | first4 = Anthony P.| last5 = Doré | first5 = Caroline J.| last6 = McCarthy | first6 = John P.| last7 = Collins | first7 = Adam L.| last8 = Fitzpatrick | first8 = Julie A.| last9 = Durighel | first9 = Giuliana| first10 = Simon D. | last10 = Taylor-Robinson| first11 = Jimmy D. | last11 = Bell| doi = 10.1038/oby.2011.142 | title = The Missing Risk: MRI and MRS Phenotyping of Abdominal Adiposity and Ectopic Fat | journal = Obesity| volume = 20 | issue = 1 | pages = 76–87 | year = 2011 | pmid = 21660078| doi-access = | s2cid = 22489848}}</ref> ('''thin-outside-fat-inside''') is used to describe lean individuals with a disproportionate amount of fat (adipose tissue) stored in their abdomen. The figure to illustrate this shows two men, both 35 years old, with a BMI of 25 kg/m2. Despite their similar size, the TOFI had 5.86 litres of internal fat, whilst the healthy control had only 1.65 litres.

Subjects defined as TOFI with body mass index (BMI) <25 kg/m2 have increased levels of many of the risk factors associated with the metabolic syndrome. This phenotype is a further refinement of "metabolically-obese normal-weight"<ref>{{cite journal | title = The "metabolically-obese," normal-weight individual | last1 = Ruderman Neil B. | last2 = Schneider | first2 = S. H. | last3 = Berchtold | first3 = P. | journal = American Journal of Clinical Nutrition |date=August 1981 | volume = 34 | issue = 8 | pages = 1617–1621 | doi = 10.1093/ajcn/34.8.1617 | pmid = 7270486 }}</ref><ref>{{Cite journal | last1 = Conus | first1 = Florence| last2 = Rabasa-Lhoret | first2 = Rémi| last3 = Péronnet | first3 = François| doi = 10.1139/H07-926 | title = Characteristics of metabolically obese normal-weight (MONW) subjects| journal = Applied Physiology, Nutrition, and Metabolism | volume = 32 | issue = 6 | pages = 4–12 | year = 2007 | pmid = 17332780 }}</ref><ref>{{cite journal | title = Normal weight obese (NWO) women: an evaluation of a candidate new syndrome| last1 = De Lorenzo | first1 = A. | last2 = Martinoli | first2 = R. | last3 = Vaia | first3 = F. | last4 = Di Renzo | first4 = L. | journal = Nutrition, Metabolism & Cardiovascular Diseases |date=December 2006 | volume = 16 | issue = 8 | pages = 513–523 | doi = 10.1016/j.numecd.2005.10.010 | pmid = 17126766 }}</ref> (MONW).

Subjects defined as TOFI have been described as being at higher risk of developing insulin resistance and type 2 diabetes due to the fact that they have reduced physical activity/VO2max, reduced insulin sensitivity, higher abdominal adiposity, and a more atherogenic lipid profile. Another important characteristic observed in this cohort is elevated levels of liver fat. It is shown that overconsumption of fructose can lead to TOFI by inducing inflammation associated cortisol release.<ref>{{Cite journal|last1=DiNicolantonio|first1=James J.|last2=Mehta|first2=Varshil|last3=Onkaramurthy|first3=Neema|last4=O'Keefe|first4=James H.|date=2017-12-07|title=Fructose-induced Inflammation and Increased Cortisol: A New Mechanism for How Sugar Induces Visceral Adiposity|journal=Progress in Cardiovascular Diseases|volume=61 |issue=1 |pages=3–9 |doi=10.1016/j.pcad.2017.12.001|issn=1873-1740|pmid=29225114}}</ref>

==Measurement== To classify an individual as TOFI, it is essential to measure their internal fat content. This is done by using magnetic resonance Imaging (MRI) or CT scanning. The parameters of the MRI scanner are manipulated to show fat as bright (white) and lean tissue as dark.

Indirect methods such as waist circumference are not suitable as individuals with an identical waist circumference can have vastly different levels of internal fat. thumb|Variation in visceral fat in men with the same waist circumference The figure clearly shows that despite having an identical waist circumference (in this example all men had a waist of 84 cm), there is considerable variation in the amount of visceral fat (volumes shown on the image in litres) present.

==Epidemiology== This is difficult to establish in the general population since the necessary imaging examinations are time-consuming and expensive; however, in a 2012 research study it was estimated that 14% of the men and 12% of the women scanned with a BMI 20–25 kg/m2 were classified as TOFI[1].

==Society and culture== Since the first scientific observations that some lean subjects could have as much, if not more, body fat internally than overweight or obese individuals,<ref>{{cite journal | title = Magnetic resonance imaging of total body fat | first1 = E. Louise | last1 = Thomas | first2 = Nadeem | last2 = Saeed | first3 = Joseph V. | last3 = Hajnal | first4 = Audrey | last4 = Brynes | first5 = Anthony P. | last5 = Goldstone | first6 = Gary | last6 = Frost | first7 = Jimmy D. | last7 = Bell | journal = Journal of Applied Physiology |date=November 1998 | volume = 85 | issue = 5 | pages = 1778–1785 | doi = 10.1152/jappl.1998.85.5.1778 | pmid = 9804581 | s2cid = 1377139 | doi-access = free }}</ref> there has been considerable media and press interest in this area of research. The first article in the popular press appeared in 2006 in ''The Guardian'',<ref>{{cite web|first=Jo |last=Revill |url=https://www.theguardian.com/science/2006/dec/10/medicineandhealth.health |title=Are you a Tofi? (That's thin on the outside, fat inside) | department = Science |work=The Observer |publisher=Guardian |date=10 December 2006 |access-date=2013-04-23}}</ref> followed by many other newspapers<ref>{{cite web |last=Derbyshire |first=David |url=https://www.telegraph.co.uk/news/uknews/1536556/Get-in-touch-with-your-inner-fat.html |title=Get in touch with your inner fat |publisher=Telegraph |date=2006-12-11 |access-date=2013-04-23 |archive-date=2012-08-31 |archive-url=https://web.archive.org/web/20120831065446/http://www.telegraph.co.uk/news/uknews/1536556/Get-in-touch-with-your-inner-fat.html |url-status=live }}</ref><ref>{{cite web|last=Cheng |first=Maria |url=https://www.usatoday.com/news/health/2007-05-10-456309910_x.htm |title=DIET: Thin people may be fat inside |publisher=Usatoday.Com |date=2007-05-10 |access-date=2013-04-23}}</ref> and television documentaries.<ref>{{cite episode |url=https://www.bbc.co.uk/programmes/p00tkv7k |station=BBC Two |series=The Men Who Made Us Fat |number=1 |title=Jacques's MRI scan |network=BBC |date=2012-06-14 |access-date=2013-04-23 |archive-date=2012-06-19 |archive-url=https://web.archive.org/web/20120619001807/http://www.bbc.co.uk/programmes/p00tkv7k |url-status=live }}</ref><ref>{{cite web|url=https://www.bbc.co.uk/news/av/health-11158546 |title=BBC News - Health Explained: What is fat? |publisher=BBC |date=2010-09-01 |access-date=2013-04-23}}</ref>

==References== {{Reflist|colwidth=25em}}

Category:Medical conditions related to obesity Category:Obesity Category:Body shape