Protein beats carbs every time – or does it?
It’s the debate that leaves athletes divided – when it comes to training fuel and a healthy diet, is it better to carb load or power up on protein?
On the one hand, we know protein helps muscle repair, but on the other consuming carbohydrates releases a slow energy burn that will fuel you for longer.
Then there’s the new wave paleo and clean eating phenomena that says we should cuts carbs all together because they’re the devil responsible for bloating, weight gain, gut issues and lethargy.
But while carbs have been steadily on the decline within health circles (OK, sweet potato aside), carbs still remain the dietary staple of choice for a majority of Australians.
Currently carbohydrates account for 45 per cent of our diet – making it our largest energy source, according to the Australian Bureau of Statistics. And while the Australian Healthy Guidelines suggest carbohydrates should make up the majority of our energy intake at 45-65 per cent (with only 20-35 per cent from fat and 15-25 per cent from protein), it’s what makes up our carbohydrate consumption that’s the worry.
The survey found within carbohydrates, 24 per cent of what we consume is made up of starch, and 20 per cent of sugar, while a third of our total energy per day comes from ‘discretionary foods’ (with no nutritional value) such as alcohol, cakes, muffins, cereal, fruit bars, pastries and biscuits.
While ‘carbs’ as a general term can’t be blamed as the major contributor behind the 63 per cent of Australians currently overweight or obese – the bad carbohydrates (the discretionary/white/refined variety) are still disputably making up a large part of our diet.
Which poses the question – perhaps a more protein-powered diet could potentially be the better and healthier choice? Not to mention there are added perks too.
And as any paleo devotee will tell you, since cutting starchy, refined, white carbs they’ve beaten that bloat.
However, like any diet that focuses on one main dietary source, it doesn’t make it perfect or the best choice for your body and dietary requirements.
Dr Nicholas Fuller, an obesity expert at the Boden Institute at the University of Sydney says while high protein diets are found to help weight loss initially, it’s been proven to not be reliably sustainable in the long-term.
“While a high protein diet results in greater weight loss over a short-term (up to three months) compared to a low fat or high carbohydrate diet, these results are not generally sustained at six to 12 months,” says Fuller.
“However this is due to a couple of main factors – firstly, carbohydrates bind water, so when we reduce them we notice a difference in body weight due to reduction of body water. Additionally, metabolising protein utilises more energy than carbohydrates so that also helps increase weight loss.”
He also notes protein is more filling so generally it can curb our snacking habits if we don’t feel hungry.
Dr Rebecca Reynolds, nutritionist and lecturer at The University of New South Wales also believes satiety is a key factor behind protein as a dietary must.
“There is some evidence that the protein macronutrient results in more satiety compared to carbohydrate and fat macronutrients,” says Reynolds.
“But there’s always error in human nutrition studies as they’re not always careful about the types of carbs tested in the diets studied – including fibre and glycemic index which both contribute to fullness and weight and are a really important factor.”
How do we know when enough is enough then? Dr Joanna McMillan, Sydney based dietitian says we will naturally know, thanks to the ‘protein leverage hypothesis’ – where our brain signals us to eat until we meet the protein threshold. So, if we eat enough early on we keep on top of our appetite and satiety.
“I recommend a quarter of the plate comes from protein-rich food at each meal for appetite control. It will help preserve muscle mass and lose more fat while losing weight,” says McMillan.
And as for the dangers – is there any harm in a protein shake for brekkie, a bun-less burger for lunch and a hearty steak for dinner?
Well, potentially, says Sydney based nutritionist Melanie McGrice. “You need to be wary of eating too much and forfeiting other core food groups as this leads to nutritional deficiencies, constipation and kidney problems.”
“We digest the amount of protein we need for building and repairing muscle and fuelling our cells, only storing a small amount of amino acids to make more proteins where needed. So, if we have excess proteins that aren’t absorbed, the kidneys work to eliminate them, however the kidney’s blood vessels are very small so they can easily get damaged by the size of proteins passing through,” says McGrice.
Additionally, McGrice says studies shown that long-term high protein diets (roughly >2g/kg body weight) can damage our kidney function.
“While there are no ‘bad’ types of proteins, there are plenty of protein-rich foods that aren’t good for us like bacon which is high in salt and saturated fat and can increase risk of heart disease.”
Interestingly, too much protein can still result in weight gain and other serious health issues. “Studies have found that a diet too high in red and processed meat can increase the risk of some types of cancers, especially bowel cancer.”
But like anything, over doing it is never a good thing. As long as you’re getting enough – while being mindful of other key food groups, it’s still packed with positives.
“Protein is essential not just for muscle repair but for new skin, liver and gut cells. Even our heart is essentially built on protein. So, because we are constantly breaking down old cells and building new, we need to consume it very regularly,” says McMillan.
And what about carbs? Do we need them at all?
Technically no, says McMillan. “We can make glucose (the principal carbohydrate of importance in the body that fuels cells in the brain) from some amino acids (the building blocks of protein).”
“The Inuits for example, eat very little carbohydrate, particularly in winter when plant foods are scarce so we can clearly do without,” says McMillan.
But whether that’s optimal for health is another matter. “Carbohydrate based foods are where we get the most fibre, minerals and vitamins like B vitamins,” says McMillan.
And it is wise to survive on protein alone? “ ‘Rabbit starvation’ – only eating lean rabbits, was something the first settlers did in America and died from – it’s far too much protein and toxic.”
So what does all this mean?
“You can follow a high protein, low carb/high fat diet – but there are concerns in the long term that high fat influences the gut microbiome in a negative way and increases your risk of insulin resistance,” says McMIllan.
“You can now take a basic gene test to see who will do better on a lower carb diet, who is likely to get fat eating too much saturated fat and who will do better with more monounsaturated fats. This is where things get interesting and where personalised nutrition seems the way of the future.”
Meat aside – is there enough protein for those on a vegetarian or plant based diet?
“It is possible to meet your daily protein through plant based sources like soy products, nuts or legumes but it’s essential to combine plant based protein sources in the one meal to ensure you still receive all the essential amino acids,” says McGrice.
So while cutting comfort carbs may seem an impossible feat for those partial to a cheese toastie or spag bol – if adding eggs, lean meat nuts and beans to your shopping list = better sleep, muscle repair, weight loss – protein may be the path you’ve been looking for. Just don’t forget to mix things up with a bowl of porridge or brown rice stir-fry along the way!
The University of Sydney’s Boden Institute is currently undertaking a weight loss trial, for those interested in participating, please see www.metabolictrial.com for more details.
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