The Truth About Protein: Is More Really Better?
Let’s start with a story. I recall a client, Stephen, who came to see me wanting to improve his body composition. After several months he could not lose the weight he planned. On initial consultation he appeared to be eating well, went to the gym, had a PT, played squash, slept well and had a balanced social life.
We went back through his diet, activity and energy requirements and looked at exactly what he was eating across the whole day. Through the food diary analysis we found the missing piece of the puzzle. Stephen wasn't simply eating protein as part of his meals; he was doubling up. Why wouldn't he? Everyone was telling him that protein was good right? Though the analysis revealed that Stephen was having 3 times the amount of protein he required. This excess protein was contributing between 300-400 extra calories a day, tipping him over his body's energy requirement. We quickly took the protein powders, bars, excess eggs and chicken out of his diet allowing Stephen to get back on track again with some sustainable weight loss.
This was such a great reminder that we may need to understand food and its role in our bodies to ensure we get the right balance for our own personal nutrition goals.
Firstly, let's give protein the attention it deserves, because protein really is rather fabulous. Protein is made up of smaller molecules called amino acids, joined together in long chains by peptide bonds. We use 20 different amino acids to build proteins within the human body, nine of which are described as essential because our bodies cannot make enough of them ourselves. We therefore need to obtain these essential amino acids from the food we eat.
And once we have them, we put them to extraordinary use. We often associate protein with muscle, but that's only one part of the story. Protein provides the building blocks needed to grow, maintain and repair tissues throughout our bodies. Our muscles, skin, hair and nails all rely on proteins, but their role goes far beyond what we can see on the outside. We need proteins to make enzymes that catalyse thousands of biochemical reactions, hormones that act as chemical messengers and antibodies that form part of our immune defence. Proteins transport substances around the body and provide structure to our cells and tissues. Even haemoglobin, which carries oxygen around our bodies in red blood cells, is a protein. Protein really does deserve its superstar status.
Our bodies are continually dismantling and rebuilding proteins. Old or damaged proteins are broken down and their amino acids can be recycled, while new proteins are being produced all the time. This continual process is known as protein turnover and is happening throughout our bodies every day.
It's a wonderfully clever system, though protein and exercise work best as a team. Eating increasing amounts of protein alone doesn't automatically mean we build increasing amounts of muscle. Resistance exercise provides the stimulus that tells our muscles they need to adapt, while dietary protein provides the amino acids required to support repair and rebuilding.
This becomes particularly important as we get older because ageing muscle can become less responsive to the anabolic effect of smaller amounts of dietary protein, something referred to as anabolic resistance. Making sure we consume adequate protein, ideally distributed across the day and combined with regular resistance exercise, can therefore become increasingly valuable for maintaining or increasing muscle mass and strength. Maintaining muscle isn't simply about looking toned either; it supports our strength, mobility and physical independence.
Protein has another useful trick up its sleeve too: it can be wonderfully satisfying. Protein-rich meals tend to help us feel fuller for longer and can therefore be useful when we're trying to manage our appetite. Protein also has a relatively high thermic effect of food, meaning that a greater proportion of its energy is used during digestion, absorption and metabolism compared with fat and carbohydrate. This combination of satiety and helping to preserve lean tissue is one reason why adequate protein can be particularly helpful when it comes to the right body composition. So far, protein is looking pretty impressive, which perhaps explains why we've become rather obsessed with getting more of it.
But do we actually need more? Interestingly, despite the impression we might get from social media and supermarket shelves, most of us in the UK aren't struggling to obtain enough protein. The National Diet and Nutrition Survey gives us a picture of what people across the UK are actually eating, and analysis indicates that protein intakes are more than sufficient across population age and income groups. The UK Reference Nutrient Intake, or RNI, for adults is 0.75g of protein per kilogram of body weight per day. That equates to around 45g of protein for someone weighing 60kg and around 56g for someone weighing 75kg. As we get older, there is also growing evidence that somewhat higher protein intakes may help support muscle mass and function, with some expert groups suggesting around 1.0–1.2g/kg/day for healthy older adults. Personally I work with clients to consume 0.8-1.6g protein a day/kg body weight depending on their individual requirements such as exercise, training regime, goals, health status and age, ensuring there are regular pulses of protein across the day and optimum times in their physical activity or training regime.
Those grams of protein can add up surprisingly quickly. Eggs, milk on cereal or yoghurt at breakfast, milk in our coffee and tea, meat, chicken, fish, tofu or beans at lunch and dinner all contribute, while cereals, grains and vegetables provide smaller amounts too. We don't necessarily need to eat or supplement with foods labelled “HIGH PROTEIN” to consume plenty of protein.
I think we can appreciate just how important protein is and consume the right amount for our individual needs. We do though need to be mindful that protein is a macronutrient. Like the other macronutrients in our diet, carbohydrate and fat, protein provides us with calories or energy. Protein provides approximately 4 calories (kcal) per gram and this is perhaps the bit that has become slightly lost in our enthusiasm for protein. Calories from protein are still calories. Suddenly, Stephen's mystery made much more sense. His high-protein yoghurt was still nutritious, his protein bar was convenient and his shake was providing good-quality protein, but he was already getting enough protein from the rest of his diet. These extras weren't replacing anything; they were simply being added on as calorie boosts.
Unlike body fat, which provides a substantial energy store, or carbohydrate, which can be stored in limited amounts as glycogen in our liver and muscles, we don't have a dedicated storage depot for spare dietary protein.
So what do we do with this excess protein? This is where protein becomes even more interesting, because chemically it is rather different from our other two macronutrients. Unlike carbohydrate and dietary fat, protein has an important additional element: nitrogen. This nitrogen is found within the amino groups of the amino acids that make up protein and is one of the reasons our bodies have to deal with excess protein rather differently from excess carbohydrate or fat.
Our bodies can't simply put surplus amino acids into a protein storage cupboard for another day. The nitrogen in the surplus protein is toxic to the body and is therefore excreted via our kidneys and urine. Our body has to dismantle the amino acids, safely deal with their nitrogen and then decide what to do with what is left.
And what is left is either used as energy...or laid down as body fat.
Once the nitrogen-containing part has been removed, the remaining carbon skeleton still contains energy. Depending on the particular amino acid and what our body needs at the time, it can enter our normal metabolic pathways and be used to produce energy, perhaps for Stephen's game of squash, or laid down as energy to use later, commonly known as a spare tyre!
But there is still a bigger picture, and that is energy balance. If, across our whole diet, we consistently consume more energy than our bodies expend, that positive energy balance can ultimately contribute to energy being stored in our adipose tissue as body fat. The fact that some of those additional calories originated from protein doesn't somehow exempt them from our overall energy intake.
And this was the simple change Stephen needed. He didn't need to stop eating protein or suddenly start counting every gram. We simply looked at how much protein he actually needed, where it was already coming from in his diet and which of the additional protein products were genuinely useful. Once the unnecessary extras were reduced, his overall energy intake was much better matched to his goals. It was a lovely reminder that a food can be nutritious and beneficial, but we still need to consider how it fits into the whole diet.
A high-protein yoghurt can be a fantastic choice. Eggs are wonderfully nutritious, while fish, lean meat, dairy, beans, lentils, nuts, seeds and soya can all make brilliant contributions to our diet. Protein powders and bars can also be incredibly convenient when they help someone meet a genuine need.
Perhaps, then, we've been asking the wrong question. Instead of constantly wondering, “How can I get more protein?”, perhaps we should be asking, “How much protein do I actually need — and am I already getting it?” Because protein really is remarkable. We need it to build and repair tissues, maintain our muscles, produce enzymes and hormones, transport substances around our bodies, support our immune system and carry out countless biochemical processes that keep us alive.
So let's absolutely celebrate protein. Let's make sure we're getting enough, enjoy a variety of good-quality animal and plant sources and perhaps pay even more attention to it as we get older. But let's also remember that little fact: protein is a macronutrient, and macronutrients provide energy. Sometimes that extra protein shake is exactly what our body needs, and sometimes, as Stephen discovered, if we're already getting plenty of protein, it may simply be extra energy that we didn't actually need.
As with so much in nutrition, the clever bit isn't simply eating more or less. It's understanding what our body needs and finding the right balance for us.
Nina Thomas
BSc (Hons), MSc, ANutr
Registered Associate Nutritionist & Food Scientist
Bridgford & Bingham Nutrition
21 Brickyard Lane
East Bridgford
Nottingham
NG13 8NJ
Call: 07958 765337
Comments