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Friday 5 April 2013

Can We Trust Nutrition Labels?

There comes a time in many-a dieter's life when going by 'approximation' becomes insufficient. Whether you're a hardcore bodybuilder looking to achieve leanness beyond compare, or just your average dieter wanting to get their body 'beach-ready'. At this time, the individuals in question will often start 'counting calories' as a way of ensuring they are consistently in a caloric deficit. 



Eventually, you start to ritually check the nutritional labels of newly bought items to ensure serving sizes, etc. meet your requirements, at which point you cease to see a 'food product' and begin to see a combination of 'proteins, fats and carbohydrates'. The question that I always ask myself (especially when I see two identical products with sparsely different nutritional values) is - "how accurate are food labels?"



The Study:

In 2010, researchers at Tufts University conducted an analysis on 40 different foods bought in various restaurants and supermarkets to determine the accuracy of stated energy contents. Their target - 'reduced-energy foods' or those containing less than 500 calories. 



You Mean To Tell Me This Label Is Inaccurate?

Their analysis indicated that the number of calories measures nearly always exceeded the number of calories declared on the nutritional labels by the manufacturers and retailers. On average, they contained 8% more calories than the labels indicated. However, the researchers noted that some individual items contained up to 200% of stated values. That's a whopping DOUBLE what was declared on the food label.



The Take-Away:

While it goes without saying that it is impossible to generalize this study to the entire restaurant and food industry, it should make us all think about our purchases of pre-packaged foods. Urabn et al. (2010) note that, if widespread, the phenomenon observed in their research could hamper efforts to self-monitor energy intake to control weight.



The Solution:

While this may be difficult for some, to others the solution will be second-nature. Prepare and cook as much of your own food as possible, using un-refined ingredients and avoid pre-made products. Although the variation of energy-content and macro nutrient composition may vary between each individual vegetable, fruit, etc. depending on factors such as soil composition, etc; you will nevertheless be able to paint a much more accurate portrait of your overall energy intake.

If you have started down the path of calorie counting, the only logical method is to reduce as much error and variance as possible, in order to maximise the effects of your hard work and efforts.



Reference:

Urban, L. E., et al. (2010). The accuracy of stated energy contents of reduced-energy, commercially prepared foods. J Am Diet Assoc, 110(1), 116-123.






Fact or Fiction: Adding Fat To Your Meal Will Lower Insulin Response

When browsing the health and fitness boards or blogs, the sheer number of claims made without any scientific evidence-base is overwhelming. This 'broscience' as it is affectionately referred to by those of us 'in the know', is akin to the Siren's of Homer's Odyssey; guiding innocent and uninitiated souls to an unwitting doom at the hands of misinformation.




Broscience Fact: Adding Fat To A Meal Will Lower The Insulin Response

It is common 'knowledge' that adding some fat to a meal will help to reduce the insulin spike it will provide. If I had to guess, I would suspect that this fallacy first came about as some eager trainee mis-read the results of the studies suggesting that fatty meals are less insulinogenic than low fat meals.


Evidence-Based Reality

Unfortunately, the picture pained by the scientific evidence is somewhat different to the commonly accepted paradigm. For example, Collier & O'Dea (1983) examined the effect of co-ingesting 50g of butter on glucose, insulin and gastric inhibitory polypeptide responses to 50g of carbohydrates (potato) or 50g protein (low fat veal) in their participants. The addition of fat to a carbohydrate meal did result in lower blood glucose levels. However, the insulin response was not reduced.


The Take-Away

So, next time you feel inclined to add a handful of nuts to your rice to 'nullify' the insulin response from your bolus carbohydrate dose, remember that you are doing so under false pretenses.

While the addition of fat to a meal may increase satiety, it may do little in the way of keeping you lean!


Reference:

Collier G, & O'Dea K. (1983). The effect of coingestion of fat on the glucose, insulin, and gastric inhibitory polypeptide responses to carbohydrate and protein. Am J Clin Nutr, 37(6):941-4.