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Could dairy be affecting your workout
Could dairy be affecting your workout

Is Dairy Affecting Your Workout?

6 minute read

Dairy products such as milk, cheese and yoghurt are immensely popular and have been enjoyed for many generations. They are a great source of protein and calcium and are widely available. Milk is often considered a “complete food” and all growing mammals need it for development. However dairy consumption is a somewhat controversial subject and some experts believe that humans are not designed to consume the milk of other animals.

While dairy is a viable source of protein, calcium and energy in general, it is presumptuous to say that it’s good for everybody’s body. Milk contains a sugar called lactose which can trigger allergies in sensitive individuals resulting in cold-like symptoms, skin rashes, abdominal bloating and upset stomachs. Some people are also sensitive to casein, a protein found in dairy. Many dairy products are also high in fat, specifically saturated fat which is high in calories and may lead to weight gain if consumed to excess.

Animal welfare can also affect the quality and healthfulness of dairy foods; milk is often tainted with hormones and antibiotics that are routinely used to maximise milk yield. In turn, we consume these potentially harmful chemicals “second hand”. Second-hand antibiotic consumption can be directly linked to antibiotic-resistant bugs like MRSA – Methicillin-Resistant Staphylococcus Aureus.


Consuming reduced lactose, skimmed/reduced fat and organic dairy products can help to avoid many of these issues.

Dairy and its effect on physical performance

There are three phases of workout nutrition which should be taken into account when discussing food and its affect on performance – pre, post and intra-workout.


While milk is a natural product containing much of the protein, carbohydrates and fat required to provide the body with energy during a workout, many people find it difficult to digest prior or during exercise and consumption of milk directly prior to an intense gym session can cause stomach upsets, diarrhoea and bloating.

The reason for this may be found in our past. Humans are the only species to consume milk past infancy and up until a few thousand years ago many of us did not have the ability to digest it as adults. Human adults require a gene that produces an enzyme called lactase in order to digest the sugar lactose found in milk. According to a study by University College London up to 90% of Europeans have this gene, while the percentage is much lower in parts of Africa, Asia and Oceania. While lactose intolerance is rare in Europeans, a general sensitivity may remain and it is important to consider this when planning pre and intra-workout nutrition.

If your stomach can handle it dairy can be excellent pre-workout food, providing your muscles with the energy it requires for exercise. In addition to the protein and carbs, the calcium contained in milk is also essential for muscle contractions. Because milk is hydrating, portable, not overly filling and readily available, it can be an excellent pre-exercise food choice and can also be consumed during exercise to sustain you during a long workout (more than 90 minutes).


The over-consumption of anything before or during a workout can cause an upset stomach though, so the best way to determine the best pre-workout routine is to start with small amounts and test your tolerance. It may be that a small quantity of dairy 1-2 hours before exercise helps to boost your energy levels and stamina. Equally, you may find it makes you sluggish in which case another source of protein and carbohydrates may be more appropriate.


Strenuous workouts can leave your muscles depleted of energy and in need of repair. After a workout your muscles need carbohydrates and protein to repair and the sooner you can refuel your muscles the faster they will recover. Milk provides the carbohydrates and protein your muscles need in a very convenient and hydrating form which is ideal for consuming immediately after exercise.


According to a study at the University of Copenhagen, dairy may also have benefits for those exercising for weight loss. The Danish research found that dairy consumers have much higher percentage of fat passing through the body into the stools than their non-dairy consuming equivalents. They believe that the calcium in dairy combines with fat to create a ‘soap-like substance’ that slides through the body without being absorbed. This is not to say people with weight-loss goals can eat dairy with impunity, but it suggests dairy products may not be as bad as previously considered when included as part of a healthy, balanced diet.

Milk – the classic muscle builder

Milk has long been used by those trying to build muscle mass as a cheap, effective source of protein. During the golden age of bodybuilding from the 1950s to early 1970s, milk was the protein supplement of choice. Many so-called hard gainers transformed themselves by following the GOMAD bodybuilding diet, short for ‘gallon of milk a day’.


Current research seems to support this and several scientific studies have confirmed that milk is indeed an effective muscle builder. Research revealed that consuming milk after exercise produced significantly better muscle gain and fat loss results compared to carb-based sports drinks or soy milk in young, healthy, male weight trainers. Specifically:

“Muscle mass gains from baseline were 6.2% (3.9 kg) in the milk drinkers, 4.4% (2.8 kg) in the soy drinkers, and 3.7% (2.4 kg) in the carbohydrate drinkers. Milk drinkers also showed a significantly greater reduction in their fat mass, which declined by 5.5% (0.8 kg) from baseline compared to both the carbohydrate group, who reduced their fat mass by 3.4% (0.5 kg), and the soy drinkers who lost only 1.5% of their baseline fat mass (0.2 kg).”

Dairy alternatives for sensitive stomachs

While reduced-lactose dairy foods can allow those with sensitivities to enjoy milk, cheese and yoghurt, some consumers may prefer to avoid dairy altogether before or after their workout. There are several similarly nutritious dairy-free alternatives available that are ideal for pre and post-workout consumption. These include:

  • Soy milk
  • Almond milk
  • Rice milk
  • Soya protein shakes
  • Rice protein shakes
  • Hemp protein shakes
  • Pea protein shakes

In addition, many people who suffer mild to moderate lactose issues have no problem with natural yoghurt or mature cheese as much of the lactose is broken down in the manufacturing process. Goat’s milk is often well tolerated when cow’s milk is not. Some dairy products are also treated with the enzyme lactase which breaks lactose down.

While dairy is rich in protein, calcium and other healthy nutrients, it’s important to understand that, as nutritionally complete as it is, it should always be eaten as part of a well-balanced diet. The over-consumption of any single type of food can result in nutrient deficiencies elsewhere. Vegetables, grains, other sources of protein, fruits, pulses and nuts all have a part to play in a balanced diet.

University College London
The Telegraph
Dairy Nutrition

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