Common fitness-related nutrition myths & misconceptions

Todays post is investigating some of the popular nutrition myths of nutrition.  In it we will discuss and put to rest a couple of major nutrition myths that appear in the health and fitness world on rotation.  James Belbin in Brighton’s leading online nutrition coach and evidence based practitioner and offers to bust these common myths in health and fitness.

What is fasted cardio and does it enhance performance?

Protein rich diets: How will it impact your health/body?

• Can you gain muscle and lose body fat at the same time?

Fasted Cardio - Your Nutritional Blueprint

What is the myth?

“Performing aerobic cardio following an overnight fast accelerates fat loss and increases sports performance via the process of a fed state.”

According to experts and the health media fasted cardio is a great method for enhancing performance. This has led to a trend of gym bunnies and bodybuilding bro’s walking uphill on a treadmill at 5am.

What gives it credence?

Fat oxidation is greater during fasted cardio and therefore a theory exists that fat loss is enhanced with enhanced fat free mass is enhanced under equivalent energy deficit/weight loss conditions.

Like with gluten, the insta-famous will report many anecdotal reviews: “XY got shredded and they do fasted cardio”, therefore it must be true and I must embark on it as well in order to achieve my goals.

Research to refute it [2]

Almost every energy balance study ever done! Plus most recently a randomised control trial by Schoenfeld et al. (2014) of 20 healthy females, split into 2 groups of 10 each completing over 4 weeks of aerobic activity.  10 fasted, 10 not-fasted with calories matched in both sets of women showed their was no difference in body weight loss of fat free mass in either group.

Take Home Message
Fasted cardio is a personal preference! Energy balance is the most important factor for fat loss.  If it suits you better to get up and exercise without eating, then go for it.  However it won’t provide any performance or health benefits over having a light breakfast.

is protein bad for your health? - Your Nutritional Blueprint

What is the myth?
This is another myth that most health seeking individuals will have heard at some point in their lives.  It comes from the advice given to individuals with pre-existing chronic kidney disease being put on a low protein diet.  This has then become one of those tales that people pass on.  The explosion of the ketogenic diet also has an impact as this diet doesn’t allow for high protein, so this adds to the discussion in a negative way.
What gives it credence?

Protein restriction is a clinically proven treatment method for chronic kidney disease.  It reduces the strain on the kidneys” in an impaired individual.  For a healthy individual it makes little difference.  The print media love to run reports claiming that “Studies show..” the risks of high protein diet, without actually reviewing the data available.

Research to refute it [3]

Again, using randomised control trials there is no shown high protein diet effects on renal function in healthy individuals as weight loss reduces risks of negative renal function and a second study found there are no clear renal-related contraindications to high protein diets in individuals with healthy kidney functiom.

Take Home Message

There is no health risk of eating a high protein diet.  In fact, if all your meals during the day contained protein, then you are more likely to eat less as protein in incredibly filling and satiating.  Depending on your goal it is recommended that you choose to eat between 0.8g/kg to 1.8kg for normal performance requirements. Its highly likely that the common factor in all successful dieters and dietary practices is consistent levels of protein.

Can you gain muscle and lose body fat at the same time? - Your Nutritional Blueprint

Yes, It is however easier to gain muscle and lose body fat at the same time in certain circumstances: ‘Newbie gains’ and ‘Muscle Memory’ are both real things! In individuals that have never done any resistance training before, as your ability to gain muscle and lose body fat is greater. Regaining muscle that has been lost due to de-training and/or poor diet is also a lot easier.

What gives it credence?

First let’s look at why it shouldn’t be possible.

For many years, most experts and the scientific weight loss literature advised that weight loss inevitably would lead to both fat and muscle loss. That was a fairly easy explanation to grasp.
Gaining muscle requires a positive energy balance (more calories consumed than burned). Losing weight requires a negative energy balance (more calories burned than consumed). So you can’t quite be in positive and negative energy balance at the same time.

To create muscle we need a calorie surplus, to build the muscle, however to lose body fat we would want to be in a deficit so that we burn fat.  In theory both cant happen a the same time, creating the myth that you can’t build muscle and lose body fat at exactly the same time.

Research to refute it [5]

These studies all proved that it is possible. This study (1) showed that by consuming high protein intakes (2.4g/kg), alongside a diet that reduced maintenance Calories by 40%, that gaining muscle and losing body fat at the same time is possible. Subjects lost 3.7kg body fat at the and gained 1.2kg lean body mass in just 4 weeks. showed that following either slow or fast rates of

Take Home Message

If you are looking to gain as much muscle as possible, losing body fat at the same time is likely sub-optimal. Being in a small calorie surplus may benefit maximal muscle gain due to the body spending less time in the post-absorptive state, as well as supporting training quality.

Referenced Studies.

[1] – Jenkins et al. (1999),  Lis et al. (2015) Biesiekierski et al. (2013)  Dickey & Kearney (2006)
[2[ – Schoenfeld et al (2014,
[3] – Martin et al. (2005)  (Wycherley et al. 2010; Tay et al. 2015)  Friedman (2004)
[4[  – (1) Schnohr et al. (1994) J. Intern. Med. (2) Knopp et al. (2003) Arterioscler. Thromb. Vasc. Biol. | (3) Mutungi et al. (2008) J. Nutr.
[5[ – (1) Longland et al. (2016) Am. J. Clin. Nutr. (2) Garthe

And who is James Belbin

James Belbin is Brightons leading online nutrition coach.  Leaving his job in the city in 2013 because of stress and ill health, his journey to coach has been a short but informative one.  Initially reversing Type 2 diabetes using Precision Nutrition’s online coaching program to lose 19kg in two years, he then decided to help more in the community.  In 2018, he upgraded his coaching badges to become an evidence based nutritionist under the tutelage of industry leader Martin McDonald. 
James runs online coaching programs to ALL, with free introductory sessions, food diary reviews, body composition analysis sessions and provides multiple service offerings depending on your goals..

Where do these nutrition myths come from?

The internet, for all its faults has provided us with un-bridled access to information.  However in a mass clamouring to be heard, there are lots of voices all speaking very loudly, and sometimes those with the largest followings (or funds behind them) get the most airtime.  Therefore it can be difficult to know if what you are reading is actually true or not.  If you are time limited it can be a real challenge to put in the ground work to know if what you are being told has some level of truth or a complete fallacy, so usually we trust what we read as gospel and try it out for ourselves.  This is never more true than with nutrition and exercise.
“what is repeated most often, starts to become a truth.”
 And that is why nutrition has become a massive battle ground for myths versus the truth.  But where do they start from?
Some of these myths will have been taught at school, university and some maybe still in medical school.  They have evolved from research and observation, or basic studies funded by a large food manufacturer.  They can be body builder “bro science” or simply just an opinion piece from a newspaper or magazine, what we call association.  N=1 it worked for me, them, us.  So it must be true,  This is also known as confirmation bias.
Researching this piece, i googled nutrition myths, and got 827,000 returns ranging from credible sources such as, Huffington Post and everything in between.  I was shocked at some of the myths i found out there, that actually this piece may contradict.
So why teach people about myths?
Omission provides no clarity.  Like telling our kids to only walk on the path.  You are not teaching them why going on the road is bad, just iterating that the path is good.  Finding out the right way rather than learning for themselves.  This becomes a disempowering message over time.
So why can you trust this article?
I am an evidence-based nutrition practitioner.  Evidence-based nutrition is a relatively new concept.  Using real science as the backdrop, relying on reviewing studies for the relevance, credibility and depth of information.  Adding in experience and critical thinking to help scope information that can be trusted.  Always open to new research and never blindly following dogma is a key attribute to evidence based practice
Our clients respect and trust us as practitioners – therefore we need to understand the roots of the myth to be able to explain the truth.
Being evidence-based does not make us infallible, we still have bias and experiences and after all we are human, however it is a good starting point to show where the weight of evidence comes from.
This article was created from scientific reviews and experience to make its recommendations.
About the Author

James Belbin is the Uk's most experienced Precision Nutrition ProCoach.  Since 2016 James has been providing clients support and guidance to optimise their nutrition and build confidence.  Currently studying evidence-based nutrition to add depth to his coaching skills, James ultimate goal is to reduce the burden of obesity on the population of the UK.

James Belbin - Precision Nutrition Elite Super-Coach



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