Nutrition

The Dangers of a Low Protein Diet

The Dangers of a Low Protein Diet

Go on the internet and type in ‘protein’ and ‘is it safe?’ You get a whole host of results coming back to you discussing whether or not it is safe and at times you can get conflicting opinions – in reality it depends on if you are looking at healthy populations or not.

For the most part, high protein diets aren’t great for those with kidney problems and other ailments such as gout, simply because kidneys filter the waste products of protein metabolism and if your kidneys are in a weakened state then this can be problematic, plus the purine content of protein foods can exacerbate problems with gout.


Let’s Flip The Argument

Moving on, has anyone actually covered how low protein diets are actually more harmful than a higher protein diet? They haven’t, so let’s flip it out on its head. Let’s start with the older populace, it’s well known that getting older has its physical consequences.


Older Population

It is widely accepted that old age brings changes to body composition even in the absence of bodyweight changes (St-Onge & Gallagher, 2010). Losses of bone mineral density and increased fat mass pose their problems. But the other one is namely the loss of muscle tissue (sarcopenia) which has it’s own host of problems.

Protein is made up of amino acids, some are essential (need to be consumed in the diet) and others are not so essential (body can make these). Leucine is the most reputable amino acid as it seems to be the potent powerhouse that attenuates proteolysis (the loss of protein) and stimulates protein synthesis (build proteins). For this reason its benefits on sarcopenia are incredible; as it has the ability to offset the age-related progressive loss of lean body mass (LBM) (Fujita & Volpi, 2006).

Why is sarcopenia bad?

It will lead to weakness and lack of durability that is vital when older. So if protein can attenuate the losses of lean body mass and prevent sarcopenia, why are we bashing its existence?

It has been shown that sarcopenic participants are three times more likely to fall over in a 2 year period compared to those that are not. Age, gender, and other confounding variables were not the culprit. It was low lean body mass (Landi et al., 2012).

Falling over in old age obviously has it’s own issues and could lead to severe injury. Sarcopenia puts the elderly at greater risk along with its effect on cardio metabolic health and all cause mortality (Landi et al., 2012; Atkins et al., 2012). Not only that ‘People over the age of 65 who ate a high-protein diet had a 28 percent lower risk of death from any cause and a 60 percent decreased risk of dying from cancer, compared to those eating low amounts of protein (Levine et al., 2014).’

Perhaps a case should be stated that increasing protein intake might improve the quality and quantity of life especially in the elderly.

low protein diet

Bone Mineral Density

So what about bone mineral density? Can protein intake have a positive effect on that? Absolutely.

Research in older women (65-77 years old) took part in a osteoporosis intervention. And it was found that those that had a higher intake of protein had higher BMD in the spine, midradius and total body compared to those that had a lower protein intake (Rapuri, Gallagher & Haynatzka, 2003). If someone falls, who is less likely to break a bone or seriously injure themselves? The guy or girl with a higher protein intake, low protein intakes have been associated with greater fracture rates (Bonjour,  Schurch & Rizzoli, 1996).

How much protein is enough?

It depends, but shooting for 20% of your energy intake would be a good place to start.


Obesity

Staying fit and healthy (37%) along with lose weight (32%) were the top two resolutions made in 2015 according to a survey completed by Nielsen. However, last year 43% of Americans say they planned to lose weight by making healthier food choices, but 76% said they did not follow a weight loss or diet program in 2014. With this is the growing rise of dietary fads – cleanses and detoxes – and despite this obesity rates don’t decline, instead they increase.

low protein diet

The problem with this is usually these diets are very low in calories, low in the volume of food and hardly sustainable and it is well known that low calorie diets can lead to losses of LBM (Trexler, Smith-Ryan & Norton, 2014). Protein can once again attenuate these losses.

You can’t starve yourself and not expect the body to fight back. What happens when you are hungry? You eat and you will eat big compensating for a harsh calorie deficit and the lack of voluminous foods.

Protein intake for obesity

This is why sufficient protein intake is so important in the possible treatment of obesity and the associated risks that come with it. Protein stimulates the release of CCK, PPY (hormones that stimulate the feeling of fullness) allowing the suppression of ghrelin to take place (Bowen, Noakes & Clifton, 2006, Brennan et al., 2008). If grehlin is high, you are hungry and can lead to that stomach grumble known as the ghrelin grumble.

One particular study showed that protein could benefit weight loss and the treatment of obesity (Weigle et al., 2005). By doubling protein intake in a diet, it lead to nearly a 500kcal decrease in caloric intake, which would have a positive impact on weight loss. Participants noted that they felt fuller and for longer once this dietary change had been made. Causing them to consume less calories. Yipee.

Protein from lean meats and meat in general is quite voluminous and has a low calorie density, which is why it’s great for staving off hunger and leaning up. Due et al., 2004 found that diets with a fat content fixed at 30% of calories produce more weight loss when high in protein (25% of energy) than when normal in protein (12% of energy) with the higher intake group losing 9.4lg compared with 5.9 kg after 6 months.


Take-Home Message

It’s odd that the government guidelines point to a moderately high carbohydrate-based diet despite the sedentary nature to a vast majority of the population, never mind the fact that the least essential macronutrient to our diet should encompass the majority of energy. I feel it’s about time everyone gets up to speed and begins to realize that perhaps it is the distinct lack of protein in our diets that may promote obesity, sarcopenia spiraling our health down a negative route.

I’m not for one second suggesting that low protein intake leads to obesity; I am well aware that it is the rise of calorie consumption. But perhaps a greater proportion of energy from protein can prevent these rises and cause people to lose fat through its mechanisms in promoting fullness and subsequently decreasing caloric intake.

An intake of 20-30% of energy from protein would appear to elicit great benefits in health and body composition, which would roughly translate to 1.4g – 2.3g per kg of bodyweight for the average person to the intermediate trainee.

 


http://onlinelibrary.wiley.com/doi/10.1111/jgs.12652/full

http://ageing.oxfordjournals.org/content/42/2/203.short

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2880224/

Bonjour JP, Schurch MA, Rizzoli R. Nutritional aspects of hip fractures. Bone 1996;18:139S–44S

Due A, Toubro S, Skov AR, Astrup A. Effect of normal-fat diets, either medium or high in protein, on body weight in overweight subjects: a randomised 1-year trial. Int J Obes Relat Metab Disord 2004;



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