Ask a Dietitian: What Are the Real Benefits of a High Protein Diet?

What comes to mind when you hear the words 'high protein diet'? Bodybuilding? Dry chicken breasts? The Atkins Diet? We've been taught to associate protein with weight loss and building muscle, but there's more to it than that. Proteins are everywhere in the human body, multitasking across departments—tissue regeneration, hormonal balance, nutrient transportation... Name a bodily function and you'll likely find proteins working hard to make everything run as it should.

Let's take a closer look at what protein is exactly, why it's so important to overall health and wellbeing, and what some of the very best food sources of protein are—inclusive of all dietary persuasions from meat eaters to vegans and everything in between.

What is protein and why do we need it?

To put it simply, proteins are the building blocks of the human body. Proteins are found in every single cell of your body. Yep, that's right. Every. Single. Cell. Proteins have numerous roles in the human body that help it to function optimally. Proteins are used to build and repair tissues, including your muscles, skin and bones. Proteins are also used to create hormones and enzymes. Proteins are even used to transport and store nutrients. Like carbohydrates and fats, proteins can also be used by the body as a source of energy.

Let's slip into something a little more scientific (a lab coat?) for a second: if we popped a protein molecule under a microscope, we would see that they are made up of lots of little amino acids. These amino acids can be either 'essential' or 'non-essential', and there are 20 types of amino acids in total. If an amino acid is non-essential, this means it can be made by the body itself, whereas an essential amino acid cannot be made by the body, and so we must get them through our diet. Different types of protein-containing foods provide different types of amino acids—this is why it is so important to enjoy a wide variety of foods!

What foods are high in protein?

Protein is found in many different foods such as meat, fish, eggs, dairy, beans, lentils, nuts, seeds, wholegrains, and soybean products. It's helpful to know that different foods contain different combinations and amounts of amino acids. Animal products and soy products tend to contain all of the 'essential' amino acids and are therefore called 'complete proteins'. Most plant proteins are lacking in one or more of the essential amino acids, and are called 'incomplete proteins'. But don't toss those lentils yet! Plant based proteins are still wonderful for the body, we just need to make sure we eat different types throughout the day and not rely on one single source.

So, how much protein should we be eating?

The jury is out amongst researchers when it comes to the golden number of grams of protein to eat per day. A safe and easy way to ensure you are getting in enough protein is to check out the Australian Dietary Guidelines. Foods are split up into 5 major food groups, and each food group has a recommended number of serves to eat per day based on age and gender. Remember that protein is found in many different types of foods, so if you're following the recommended serves (particularly for lean meats and legumes, dairy, and wholegrains) you'll be sure to be getting in a nice amount to keep your body healthy and strong.

What's the deal with high protein diets?

We've all heard about high protein diets or know someone who has tried one. A high protein diet is when someone consumes a higher ratio of protein in comparison to carbohydrates and fat. There are several benefits to consuming a high protein diet, including the following:

• Eating a high protein diet helps you feel fuller for longer by suppressing the effects of a ghrelin, the hormone that makes your stomach grumble. Feeling fuller for longer means that you are less likely to consume as many kilojoules throughout the day, therefore leading to loss of weight. 
• A high protein diet has been shown to increase your metabolic rate due to the increased amount of energy required to digest and absorb protein molecules than those in carbohydrates. This increased thermic effect can help to burn body fat.
• More protein in the diet can help maintain lean muscle mass by building, maintaining, and repairing muscle tissue. This is particularly important as we age, when we are more prone to muscle-loss, and also after exercise for muscle repair.
• It's good for bone health. Eating enough protein can help to maintain bone strength and bone mass, reducing the risk of fractures and osteoporosis.
• A high protein diet can reduce cravings by boosting the effects of dopamine in our brain.

This is all sounding pretty good, right? So are there any downsides to eating a high protein diet? In short, yes. As we mentioned before, protein is in fact used as a source of energy in the body, and in excessive amounts, this energy can be stored in the form of body fat. Another common consequence when people consume too much protein and subsequently reduce their intake of other healthy foods, is that their fibre intake decreases, causing constipation. Increasing protein intake, particularly in the form of animal-based proteins, and neglecting the consumption of other food groups, has also been associated with an increased risk of heart disease and certain cancers. 

As we dietitians love to say, it really is all about balance. For the average person looking to maintain their health, follow the Australian Dietary Guidelines and choose quality sources wherever possible to ensure you reap the benefits while avoiding any of the risks of excessive protein intake. As always, if you're unsure about what's right for you, speak with a registered dietitian for specific, individualised advice. 

Always seek the guidance of your doctor or other qualified health professional with any questions you may have regarding your health or a medical condition.

Explore more content like this in our series, Ask a Dietitian.

Health & Performance Collective is the brainchild of Sydney Dietitians Jessica Spendlove and Chloe McLeod. They use their 20 years of combined knowledge and skills as dietitians to work with motivated people to live and perform at their best.

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