Protein can certainly be classed as an energy source, but it should not be your first port of call. Protein is used primarily for other demands such as tissue repair, enzymes and hormones. Additionally, it takes longer for your body to convert protein into energy, especially when compared to the rapid energy boost you get from carbohydrates.
Protein is an absolutely essential micronutrient for the body. It helps to repair tissue and muscle, as well as preventing muscular degeneration, creating enzymes and hormones for the body, and much more. So how does Protein contribute to sustained energy levels throughout the day?
The three macronutrients are: fats, Carbohydrates and Proteins. Proteins are constructed of amino acids, which are commonly referred to as the building blocks of protein. Protein is found in a wide range of foods, including meats, dairy products, nuts, seeds and more. In today's fitness generation, many people get a large proportion of their protein from protein supplements such as powder shakes and bars. This is a good way to ensure a sufficient daily protein intake.
One thing which makes protein unique form the other macronutrients, is that our bodies do not store it in excess. When our body needs protein, there is no store or reserve from which our cells can receive protein from, and this is why it is so important that our diets are sufficient in protein.
A generally recognised rule of thumb, is that the average healthy diet will include 1 gram or protein, for every 2lbs of an individual's body weight. This will increase to 1 gram of protein for every 1lb of body weight for an athlete.
You may have recognised that protein often makes you feel full for longer. Numerous studies have supported the claim that protein significantly increases satiety and decreases hunger pangs. This is why starting the day with a protein-rich meal can be a fantastic aid to weight-loss, in order to prevent feelings of hunger later in the day.
Foods which are high in carbohydrates cause a spike in blood sugar, and release of insulin which causes tiredness, and so can often have the reverse desired effect.
When you consume protein, your blood sugar and insulin levels remain more manageable. Glucose is released into the bloodstream at a more regular rate, which prevents the sugar crash. To conclude, carbohydrates may give you a quick burst of energy, but protein will provide a longer, more sustained and manageable source of energy.
As a result of this, I would recommend incorporating protein into all of your meals throughout the day, to ensure you have a ready supply of protein for muscular function, as well as a sustained source of energy. Try to avoid preparing meals with too-high a carbohydrate ratio, to avoid the sugar crash which will diminish your alertness and leave you feeling tired.
Once you have consumed protein, the human body breaks it down into individual amino acids, so that the cells can use them for specific roles. Around 75% of amino acids are used to synthesize new proteins, which are used to build and repair tissues. Amino Acids are also used for producing enzymes which digest food and kick-start your metabolism. Amino acids which aren't re-gathered to form proteins help to make neurotransmitters and hormones. In a chemical sense, Amino acids are quite similar to glucose, excluding the fact that they contain nitrogen. What this means, is that even once the proteins have been broken down into amino acids, they then must have the nitrogen removed. Only once this nitrogen is gone can they turn into glucose and/or fatty acids. Regardless of the outcome, these give you energy, and this process, with plenty of extra steps, contributes to the prolonged energy release, as opposed to that of carbohydrates.
Once protein is converted into energy, it provides four calories per gram consumed, (Which matches that provided by carbohydrates.) Fats on the other hand, provide 9 calories per gram, making them the leading source of energy. However, as fat is such a concentrated source of energy, any excess fats, will be stored as fat! When the body needs energy, it will first turn to glucose from carbohydrates, and then fatty acids. Providing your body is sufficient in both of these energy sources, your body will not consume protein as energy.
The muscles in the body will use fatty acids while you are at rest, however when you engage in activity, they will require glucose. Converting amino acids into glucose will help to fulfil this demand, but when protein is used as the energy source, the body also produces ammonia. During a workout, ammonia can easily build up in the muscles, resulting in fatigue. Using protein as an energy source in this situation will also deplete the proteins necessary for your muscles.
Toby Hone
BSc (hons) Sport and Exercise Science
