In modern times, we have a love/hate relationship with cheese. We love fat in our cheese for the mouth feel and the taste, and for the way the fat in cheese acts when it is cooked. At the same time, though, we are leery of the effects of fat on us, both appearance wise and health wise.
Traditionally, in Northern Europe, the only way to get fats in your diet was through animal fats. Your body needs a certain amount of fat, otherwise it cannot process vitamins which are fat soluble. Fat was at such a premium that Jews saved even chicken fat for cooking, calling it “schmalz.”
The fat content of milk is called “butterfat”, and most of it is in the cream of the milk. Farmers would skim off the cream at the top of milk, and sell it to richer people, or use it to make desirable cheeses that would fetch a good price at market. Full-fat or higher-fat content cheeses were for richer folk. When the farmers made cheese for themselves, they made it from the milk left over, and skim milked cheeses came about. Many traditional and now-desirable cheeses evolved to be made specifically from skim milk. One of the most famous skim milk cheeses is Parmesan.
A traditional French gourmand approach to the question of fat in cheese was making sure there’s *lots*. This approach entails ensuring that there was at least x amount of fat in a cheese, rather than the modern focus on not wanting more than x amount. Thus the now-traditional labels of double-cream (a minimum of 60% butterfat in the cheese) and triple-cream (a minimum of 70% butterfat in the cheese) came about.
Such a traditional joie-de-vivre approach to cheese makes today’s dieticians faint.
After several decades of being educated by dieticians in newspapers and government publications, consumers seem to be responding by indicating that they want and will pay more for reduced fat cheeses, thus flipping on its head the whole history of what level of fat content in cheese was desirable.
There are and always have been “natural” reduced fat cheeses that consumers can buy, such as cottage cheese. But what consumers seem to be saying is that they want the full-fat cheese types they like, but in reduced fat varieties. This poses a problem to cheesemakers.
Commercial “reduced fat” cheeses are in fact “artificially reduced fat.” Rather than making a cheese which traditionally just naturally has less fat in it, the manufacturer has made a traditionally higher fat cheese recipe, reduced the fat content in it, and compensated by using emulsifiers. The problem is that when you take cheeses traditionally made from whole milk, such as cheddar, and try to make them from skim milk instead, the cheese ends up with all the appeal of recycled sawdust, as the cheese was never designed for that kind of milk. Once people taste them, they aren’t racing back to the store to buy them again. They don’t like the texture, or the taste, or how the cheese acts in cooking.
Fat Content Categories
Different countries and different agencies measure fat content differently; there are no standards. As well, there are informal categories for consumers, and formal categories for producers.
The British Cardiac Patients Association simply classifies cheeses as low-fat, medium-fat, and high-fat.
The British Cheese Board has six fat categories for cheese:
TermDefinitionFat freefat content of less than .15%Very low fatfat content of less than 1%Low fatfat content of less than 3%Half fat50% less than full fatReduced fat25% less fat than full fatFull fat34 to 35% fat
In German law, there are eight fat categories for cheese.
TermDefinitionLow fatUnder 10%Quarter fat At least 10%Half fat cheeseAt least 20%Three quarter fatAt least 30%Regular fat cheeseAt least 40%Full fat cheeseAt least 45%Cream cheeseAt least 50%Double creamAt least 60% to max. 87%
Fat in dry matter
Sometimes you may see the phrase “fat in dry matter” (fat i.d.m.). That’s different from other stated fat contents; it takes into account water in the cheese, and water of course doesn’t have fat in. It’s used by professional cheesemakers because it is more; it is more reliable because, as a cheese ages and water evaporates from it, percentages can change. Dry matter doesn’t evaporate, so the ratio of fat to dry matter won’t change.
As a rule of thumb, you use the following multipliers to roughly arrive at the “fat in dry matter” measurement:
- Cream cheeses: multiply fat content by 0.3
- Soft cheeses: multiply fat content by 0.5
- Semi-firm cheeses: multiply fat content by 0.6
- Firm and hard cheeses: multiply fat content by 0.7
Fat free cheeses don’t melt well, and have reduced flavour to boot. Use them in dishes where it’s not mission critical that the cheese melts and spreads, and boost the flavour of the dish up with a bit more spice or herb.
Reduced-fat cheeses with emulsifiers in them have at least one thing going for them compared to fat-free cheeses. The emulsifiers in them often melt well, so the same physical effect (if not the taste) of real cheese can be achieved in cooking.
Fat is what carries the flavour of cheese to your tongue, and makes accessible to your body the vitamins A, D, E and K that are in cheese.
You can’t always go by intuition. Camembert and Brie might seem higher in fat than Cheddar, for instance, but the numbers show otherwise. 100g of Camembert has 23.7g of fat, 100g of Brie has 26.9g fat, and 100g of Cheddar has 34.4g of fat.
A surprising 2010 study at Australia’s Queensland Institute of Medical Research (QIMR) Cancer and Population Studies Group, conducted over 16 years, found that people who consumed full-fat dairy had 70% less chance of death by stroke or heart disease. The researchers speculated afterwards that there may be nutrients in milk fat that counteract what we would expect to be the negative effects of the fat.  One vitamin that has been possibly associated with heart health is K2, which milk fat is a good source of. 
Note that neither of these studies are enough to discredit the current accepted thinking that full-fat cheese is bad for you. The Australian researchers concluded, “Overall intake of dairy products was not associated with mortality [ed: in this study.] A possible beneficial association between intake of full-fat dairy and cardiovascular mortality needs further assessment and confirmation.” 
Literature & Lore
“When you take a lot of the fat out, essentially cheese will turn into an eraser.” — Gregory D. Miller. Quoted in: Fountain, Henry. Asked to Get Slim, Cheese Resists. New York Times. 7 August 2012. Page D1.
 M Bonthuis, M C B Hughes, T I Ibiebele, A C Green and J C van der Pols. Dairy consumption and patterns of mortality of Australian adults. European Journal of Clinical Nutrition (2010) 64, 569–577; doi:10.1038/ejcn.2010.45; published online 7 April 2010
 Johanna M. Geleijnse, Cees Vermeer, Diederick E. Grobbee, Leon J. Schurgers, Marjo H. J. Knapen, Irene M. van der Meer, Albert Hofman, and Jacqueline C. M. Witteman. Dietary Intake of Menaquinone Is Associated with a Reduced Risk of Coronary Heart Disease: The Rotterdam Study. J. Nutr. November 1, 2004 vol. 134 no. 11 3100-3105
Bergader Privatkäserei GmbH. Cheese encyclopaedia. Retrieved November 2012 from http://www.bergader.de/en/encyclopedia.html
Fink, Leslie. Say Cheese. WeightWatchers. Retrieved November 2012 from http://www.weightwatchers.com/util/art/index_art.aspx?tabnum=1&art_id=55841
Maddison, Richard. Cheeses – fat content. Nottingham, England: The British Cardiac Patients Association. 2012. Retrieved November 2012 from http://www.bcpa.co.uk/factsheets/FatContentOfCheeses.htm
Orlinksy, Katie. While Warning About Fat, U.S. Pushes Cheese Sales. New York Times. 7 November 2010. Page A1.