If we were being flippant, our answer to the question “how much protein is there in milk?” would be, “how long is a piece of string?” or, more accurately “what kind of milk”. Being less flip we’ll assume that by “milk” you mean cow's’ milk as sold in shops around the world Even here, however, there are variations depending on how the milk is processed.
All figures are based on a 100g serving
- Whole milk (3.25% fat)
Just as it comes from the cow (well, in most places, plus pasteurization). Whole milk provides around 3.2g of protein and 3.3g of fat, of which only 1.87g is saturated.
- Reduced-fat milk (2% fat)
In the old days, there was whole-fat milk, semi-skimmed milk and skimmed milk. Now semi-skimmed milk comes in two forms, reduced-fat milk and low-fat milk, which will discuss in a bit. Reduced-fat milk actually has slightly more protein per 100g serving, 3.3g to be precise and, of course, slightly less fat, 2g of which 1.26g is saturated.
- Low-fat milk (1% fat)
Low-fat milk has 3.4g of protein per serving and 1g of fat of which 0.63g is saturated.
- Skimmed milk
Skimmed milk also has 3.4g of protein per serving but only 0.1g of fat of which 0.05g is saturated.
Milk and Fat
Although the main purpose of this article is to talk about protein, we’d like to take a little detour to talk about fat since it is, for want of a better term, the “headline” value when talking about milk, for example, it determines the colour on the top of the container. Even full-fat milk only has about 3.25% fat in it, which is relatively low. The reason why full-fat milk has been given a bad press in certain circles is because around 70% of the fat it contains is saturated and for years saturated fat has been widely labeled as unhealthy. Over recent years, however, it has become increasingly obvious that, as is so often the case in life, the situation is rather more complicated than some people like to make out.
In scientific terms, fat is a combination of glycerol and fatty acids. The difference between saturated, monounsaturated and polyunsaturated refers to the way the molecules are structured. That’s all. The reason why saturated fats have developed a reputation as health villains dates back to the 1970s when heart disease in the U.S. turned from a minor issue into one of the leading causes of death. Researchers discovered that eating saturated fats appeared to raise the level of cholesterol in the blood. They also discovered that people with heart disease often had high levels of cholesterol. Hence, they concluded, that saturated fats increased the risk of heart disease. What only came to light later is that there are two kinds of cholesterol: High-Density Lipoprotein and Low-Density Lipoprotein. At this point in time, HDL is regarded as “good” cholesterol and LDL as “bad” cholesterol. Except that LDL can be subdivided into Large LDL and Small, Dense LDL and it’s only the latter which can be really bad for you as it can permeate the arterial wall and hence very well could contribute to heart disease. Hence the early studies on “cholesterol” may well have had a valid point in the sense that there could well be a correlation between high levels of total cholesterol and heart disease, but the initial (and often ongoing) advice to avoid saturated fats as much as possible now looks far too sweeping. It also ignores the fact that heart disease started to become a major issue in the U.S. (and indeed UK and various other countries) around about the 1970s, which was a time when lifestyles became much more sedentary and obesity started to become a serious problem. In short, while there are all kinds of reasons to avoid consuming excess fat and to work to remove excess fat from the body, a certain level of fat is necessary and healthy and the fact that dairy milk is high in saturated fats does nothing to alter the high level of health benefits it offers overall.
Getting back to protein
The amount of protein in milk is more or less the same regardless of what sort you consume, although it does go up slightly as the level of fat goes down. About 80% of the protein content in any kind of milk is made up of casein and the rest is made of whey, which is possibly the opposite of what you would expect given the prevalence and price of whey-based products compared to their casein-based counterparts.
Casein is an insoluble protein whereas whey is a soluble protein. As such, casein is absorbed (relatively) slowly by the body (at about half the rate of whey), whereas whey is much quicker to act. When you mix a pre- or post-workout shake with milk, you add extra whey and an element of casein as well. If you just use water, you get all the whey goodness, but without the casein. Casein supplements are often sold as “night-time” products to aid in muscle development and regeneration while you sleep. They might also be a good choice for people who simply want a slow-release protein to help them stave off hunger pangs during the day.
Milk and carbohydrate
Protein and complex carbohydrates are the staples of many healthy meals. They fill us up and keep us feeling comfortably full over the long term. Milk is about 5% carbohydrate, most of which is in the form of lactose. Because some people lack the digestive enzyme to process lactose, they are unable to digest standard milk properly. There are now some “lactose free” milks available for people in this category.
All kinds of other goodness
Milk is full of all kinds of vitamins and minerals and is particularly rich in calcium. The importance of calcium for health and wellness should never be underestimated. While most exercise is about developing the muscles, strong muscles need strong bones to hold them and those who enjoy contact sports should pay particular attention to their calcium intake.
Even though diet gurus may shake their heads at the fat content in dairy milk (and in particular the saturated fat content), the fact is that a certain level of fat is necessary for health and if you’re leading even a moderately active life, you’re highly unlikely to pile on the pounds by drinking cow’s milk. You are, however going to benefit from a whole lot of nutritional value. For those who, for whatever reason, still prefer to avoid cow’s milk, there are a range of alternatives varying from goat’s milk to nut milks, which can also offer high levels of protein and various other benefits.