One of my favorite things about the ketogenic lifestyle is all the dairy. As long as you have no allergy or sensitivity, real cream, rich cheeses, and full-fat, thick yogurts can all be a part of a nutritional ketogenic diet. However, not all forms of dairy are low-carb and keto-friendly.
Dairy products are primarily made up of water, protein, fat, and lactose (a.k.a. milk sugar), in various quantities depending on what it is. The acceptability of any dairy product on a ketogenic way of eating depends entirely on that composition. Milk products that are low in lactose content but high in fats and proteins are generally more acceptable, whereas dairy that is higher in both water and lactose are off limits. You will generally want to avoid anything that is low-fat, so stay out of yogurts and cheeses, etc., that are made with 2%, 1%, or skim (fat-free) milk.
There are several different types of dairy, and it is important to know what they are so you can discern whether or not they are appropriate on a ketogenic protocol.
This encompasses both milk (all categories of fat as well as raw) and cream.
Milk, even raw and whole milk, is mostly water. Milks with lower fat content universally have more sugar per serving than whole milk. When the fat is removed from the milk, you need more of the remaining liquid to obtain the same size serving and so the less fat in the milk, the more of the leftover sugary water you get. The fat content of whole milk is generally around 3.2%, and it contains slightly under 8 grams of both fat and protein and about 12 grams sugar per one cup serving, making it a poor choice.
We do occasionally see questions about raw milk, and unfortunately it is also not appropriate for a ketogenic lifestyle. It is harder to find "official" stats on raw milk, however the general consensus amongst producers and connoisseurs is that it contains approximately 9-10 grams fat, 9-10 grams protein, and 12 grams sugar per one cup serving, making its macronutrient profile almost identical to processed whole milk. Therefore, it is also a poor choice for general use, however it may be used in homemade fermented products and cheeses, as desired.
Goat's milk is also a poor choice, coming in at 10 grams fat, 9 grams protein, and 11 grams carbohydrate per cup.
Cream is obtained by allowing expressed milk to rest, during which time the butterfat (cream) in the milk rises to the top in a layer and is skimmed off. Heavy whipping cream, which we commonly recommend in the United States, can vary a bit in fat content but it is generally in the ballpark of 30-35% fat. A one cup serving contains almost 86 grams fat, just under 7 grams protein, and only 6.9 total sugars. Because of how rich cream is, you usually don't need as much to achieve similar results as milk, and the typical serving size is much smaller (tablespoons versus cups). Thus, the high-fat and low-sugar content make heavy whipping cream an excellent choice.
Half-n-half is a type of cream very commonly available world-wide and is typically used in coffee and tea. It is composed of half cream and half milk, which both raises the sugar and lowers the fat content considerably. One cup of half-n-half contains 25 grams fat, 7.6 grams protein, and a total of 11.4 carbs, 10 of which are sugar. Light cream has a similar macronutrient profile. Half-n-half and light creams could be best described as falling into a grey area for ketogenic eating. It's not the worst choice you could make, but using full-on cream would certainly be much better. We generally recommend using heavier creams (which you can thin out with water, if needed, for texture), however if you are in a location where this is your only option (such as a restaurant) then half-n-half or a light cream is acceptable to use upon occasion.
Other varieties of cream may be available depending on your location. For example, in the United Kingdom you may have a hard time sourcing heavy cream, but double cream is usually readily found. Double cream is actually slightly higher in fat content than heavy cream (around 40% compared to mid-30%) and is an excellent alternative when the latter isn't widely available. It contains approximately 120 grams fat per one cup serving, and has a similar protein and sugar content to heavy cream.
2. Fermented Milks
This category includes milk products like yogurt or kefir. Fermented milk products may or may not be acceptable on a low-carb diet for those with severe insulin resistance, depending on personal tolerance levels.
While these products are made from milk, the sugar content of the end-product is greatly reduced. During fermentation, microorganisms feed off the lactose in the milk and leave behind lactic acid as waste (the increased acidity is what gives these products their tang), thickening it in the process. In fermented milk products that are made from whole milk, the vast majority of the milk sugar is "eaten" during this process, leaving a relatively low carbohydrate count. A one cup serving of full fat, plain Greek yogurt contains approximately 8 grams fat, 22 grams protein, and 8 grams sugar.
As long as your yogurt or other fermented milk product is made from full-fat milk and does not contain added sugars or flavorings, the typical ketonian may enjoy these foods in small quantities.
3. Fermented Creams
This is basically sour cream (and crème fraîche) and it is made in a similar fashion to other fermented milk products, however it begins with fattier cream instead of thinner milk. Full-fat sour cream has very little lactose left over after fermentation, and therefore may be enjoyed regularly. One cup of full-fat sour cream contains a little over 44 grams fat, 5 grams protein, and a hair under 8 grams sugar, but since we typically only use much smaller amounts (think tablespoons instead of cups for your serving) it's a very acceptable ketogenic food.
4. Evaporated and Condensed Milks
These are products that begin with milk and are cooked for extended periods at lower heat in order to allow much of the water content to evaporate. The longer the milk cooks, the more condensed it becomes. These products are both very high in sugar and should be avoided. Evaporated milk contains 19 grams fat, 17 grams protein, and 25 grams sugar per cup. Condensed milk is almost universally sweetened and contains 26 grams fat, 24 grams protein, and a whopping 166 grams of sugar in one cup.
Protip: Don't use condensed milk!
Cheeses are made in a relatively similar way to fermented milk products. In cheese-making, the protein content of the milk is allowed to coagulate (thicken), and various types of bacteria or mold are used (depending on type of cheese) which then feed on the lactose and, over time, raise the acidity of the product by leaving behind lactic acid as waste. The water content is then drained off and the solids are pressed into molds.
The nutrient content of cheese can vary pretty widely depending on type, so it's more difficult to give a definite set of nutrition parameters. In general the hard cheeses (such as cheddar or Parmesan) will have the most consistent carbohydrate content across types, usually coming in at around 1 carb per ounce (a typical serving). Soft cheeses vary in carb count (0.6 carbs per ounce for whole milk mozzarella, for example) and are also acceptable. As always, we typically only use full-fat cheeses.
Butter is made from churning cream and then draining off the water content (buttermilk) that separates. The small amount of lactose that was in the starting cream is almost entirely left behind in the drained off buttermilk, thus butter is pretty much pure fat. It contains 184 grams fat, almost 2 grams protein, and a minuscule 0.1 grams sugar (same as the carb total) in one cup. Butter is a fat powerhouse!
A related product seen more frequently these days is ghee. Ghee is butter that has been clarified and has the milk solids removed. Because you heat butter for a long time during this process, it has a very nutty, toasted flavor. The macronutrient content of ghee is almost identical to butter.
Originally, buttermilk was the liquid leftover and drained off after churning cream into butter. However, what we tend to think of as buttermilk is actually a cultured milk product. Because it is partially fermented by bacteria cultures, it has a sour or acidic taste. Unfortunately this cultured buttermilk is made with low-fat milk, and thus begins and ends the fermenting process with a much higher sugar content. The finished product still has a substantial amount of lactose left behind. In fact, both original and cultured buttermilk have a similar macronutrient profile to whole milk and are thus not keto friendly foods.
Hopefully you now have a much greater understanding of the various dairy products we can and cannot consume on a ketogenic lifestyle. Knowledge is power, so stay informed and stay keto!
We've been asked a lot about cottage cheese. Cottage cheese is technically a cheese product. Essentially, it is made by curdling cheese, and then only lightly pressing it so some of the liquid whey remains. The smaller curd type is usually more acidic and made without rennet (enzymes that speed up the curdling process). The larger curd style is less acidic and rennet is used in the curdling process.
Full-fat cottage cheese tends to contain a little over 4 grams of fat, and 3 grams total carbohydrate (2.67 grams of which are sugar) per 100 gram serving. The carb count is similar, per ounce, to other cheeses, making it an acceptable choice as long as you're not consuming low-fat or fat-free versions, both of which contain around double the carbs per serving.
However, the thing to keep in mind when considering cottage cheese as a potentially friendly food is that most people do not typically consume cottage cheese alone. Condiments that tend to be used most frequently with cottage cheese are fruit (especially high carb pineapples) and granola, neither of which are keto compliant.
Our suggestion is that cottage cheese may be acceptable in your low-carb lifestyle when using it in recipes or eaten alone, but not if you will be consuming it with the traditional, high-carbohydrate accompaniments.