However, several studies including a study by Revedin et al (2010) found there was evidence from at least 30,000 years ago that starch grains were found on the surfaces of grinding tools from a variety of geographical and environmental sites. The sites showed signs of plant food processing and that the production of flour was possibly a widespread practice across Europe. So, we might well have been consuming carbohydrates for a much more significant period of time than previously thought.
Now back to the present day.
A recent meta-analysis of 23 randomised controlled trials by Hu et al (2012) looked at the effects of low-carbohydrate diets (less than 45% of energy from carbohydrates) versus low-fat diets (less than 30% of energy from fat) on metabolic risk factors. What is interesting is the findings showed a general lack of difference in effectiveness for improving metabolic risk factors.
This is important as it highlights that neither one particular diet was any better than the other. Furthermore, this has implications for the average gym goer who might think they need to “cut out carbs” to be healthy. Clearly, they don’t.
Carbohydrates are a diverse class of compounds that provide several specific functions within the body. Carbohydrates support healthy blood glucose control, gastrointestinal function, prevention of several diseases and conditions, and provision of important nutrients to the body.
Carbohydrates are not considered to be “essential” but they will certainly benefit your training, and as you know lifting weights is probably the best thing you can do to prevent lean body mass loss. Winner.
Different carbohydrates sources are better choices than others due to their ability to promote fullness and provide vitamins and minerals. So, nutrient dense and fiber dense is the message. Fibre can be found in vegetables, whole grains, legumes, fruits, nuts, and seeds.
So, what does this mean to the average gym goer who is looking to improve health markers and lose some body fat?
Fat loss is ultimately about calories in vs calories out. How you choose to create a caloric deficit is up to you but it makes sense to go with preference as this will lead to greater adherence. So, whilst some people will take the low-carb approach it probably goes against their general food preferences and will more than likely lead to failure as it's not sustainable.
Now, we're not against low-carb diets. On the contrary. Research and practical experience show that low-carb diets can help people lose weight.
However, the critical point is whether this is sustainable.
Our conclusion, based on a review of the research and our practical experience with hundreds of personal training clients is if you’re a person who’s considered sedentary, you might be able to get away with it. For a short period of time.
But, if you’re someone who likes to train and who works out regularly, eating a low-carb diet for a significant length of time may be detrimental to your health in terms of a sluggish metabolism, lower levels of strength/muscle building hormones and higher levels of stress hormones.
So, the take-home here is:
If you train or exercise regularly it would be wise to include carbohydrates in your diet.
The amount is dependant on your size and activity levels.
Try to include nutrient dense and fiber dense foods but ultimately, if you want to lose weight or body fat you will need to be in caloric deficit - how you go about this should be dictated by preference as this will lead to greater adherence to the diet.
Revedin A, et al. Thirty thousand-year-old evidence of plant food processing. Proceedings of the National Academy of Sciences. 2010;107(44):18815–18819
Hu T, et al. Effects of Low-Carbohydrate Diets Versus Low-Fat Diets on Metabolic Risk Factors: A Meta-Analysis of Randomized Controlled Clinical Trials. Am J Epidemiol. 2012 Oct 1;176 Suppl 7: S44-54.
Michael J. Gibney, Susan A. Lanham-New, Aedin Cassidy, Hester H. Vorster. Introduction to Human Nutrition, 2nd Edition. 2009. Wiley - Blackwell
Liska, D., Quinn, S., Lukaczer, D., Jones, D., Lerman, R.H. Clinical Nutrition: A Functional Approach. 2nd ed. Institute for Functional Medicine, Gig Harbor, WA; 2004.