When reading articles and studies, it is always important to be selective and critical about what you are reading. While industry professionals are always spouting new sources of information, there is always the need to take that information with a grain of salt. For example, I read an article the other day by a well known individual in the sports, exercise, bodybuilding and coaching community. The article examined certain rules for carbohydrate intake for the best body composition. While the essence of the article was in the right direction, there were a couple of misinformed points, which when taken at face value could result in poor future dietary practices. Let’s take a look at some of the points made in the article in question and examine why some of the advice given may not have been the most accurate.
1. Eliminate Grains - Particularly Wheat
This was the first piece of advice from the article and one concept that I personally found hardest to swallow. While grains have not been a staple in everyday life since the advent of agriculture some 10,000 odd years ago (a relatively short period of time in the evolution of the modern day human), it has become an important source of nutrition for a majority of the world’s population. The call to eliminate grains from your diet doesn’t take into account that they are an excellent source of several vitamins and minerals including thiamine, zinc, phosphorous, magnesium and iron. Grains are also one of the cheapest and most important sources of energy and consumption of wholegrains provide a whole host of antioxidants, phyto-oestrogens and phytosterols, all of which are able to help with a variety of chronic diseases.
The point made in the article about wheat influencing blood sugars in a similar fashion to common table sugar can also be quite misleading. While it is essentially true, many people don’t realise that sugar and wheat products generally have a medium or moderate GI. Comparing wheat to sugar is often done as a fear mongering tactic for consumers who see sugar as a culprit. The point that should have been put forward is that one should consume carbohydrates coming from predominantly whole grain cereals with a reduction in high calorie refined grain products.
2. Eliminate Grains Due to Gliadin/Gluten
Gliadin is a glycoprotein found predominantly in wheat and plants belonging to the Triticum family. It is one of the main allergens found in wheat and can cause quite severe reactions for those allergic to the protein. Gluten, also a protein found in wheat and other grains such as barley and rye is often a problem for people with gluten sensitivity and coeliac disease, in which the consumption of the protein results in several uncomfortable symptoms. The last couple of years, it seems eliminating wheat and gluten from your diet has become somewhat of a fad. While discontinuing grains consumption if you have a wheat allergy, gluten sensitivity or coeliac disease is always recommended, eliminating grains or other substantial food groups from your diet without reason or professional advice could put you at risk of missing out on crucial sources of important nutrients. It’s also wise to remember that not all grains contain gliadin or gluten such as rice or corn.
3. Carbs Should Be Fibrous
I tend to agree with this statement. Consuming a diet rich in soluble and insoluble fibre as well as resistant starch is a fantastic way to promote long term good health as it has the ability to reduce cholesterol absorption, lower the glycaemic index of a meal and promote healthy gut flora. While fruits and vegetables are good sources of fibre, they generally contain small amounts per serve. For example, 100g of celery only has 1.6g of fibre. Compare this to a cereal such as Kellogg’s All Bran Flakes which provides the same amount of fibre in 10g of cereal.
In addition, while it is true that high fibre foods generally bring about a lower insulin response than a food low in fibre, it is important to understand that unhealthy foods such as chocolate cake or donuts also bring about a lower insulin response. In addition, the reason why fibrous fruits and vegetables are such a great food for body composition lies more in the fact that they are low in calories, are filling and have a blunted insulin response due to its small amount of carbs rather than its fibre content. The major point would be to ensure you have plenty and a wide variety of fruits and vegetables aiming for 2-4 serves of fruit per day and 5-7 serves of vegetables per day, while encouraging fibre consumption coming from fruits, vegetables and less energy dense wholegrain products. You should be aiming for a daily fibre intake of 25-30g per day. The only time you would want less fibre is before competition as the feeling of fullness can be quite uncomfortable at a time where you generally need constant refuelling. A lower fibre consumption is also recommended if you are suffering from diarrhoea or constipation.
4. Darker Fruits & Antioxidants
Darker coloured fruits and vegetables tend to have strong antioxidant levels and it is always great to consume them. However, berries, often considered the highest source of antioxidants on a pound for pound basis are often quite expensive and does not fit into everybody’s budgets. Fruit consumption is important and as long as you’re having a 2-4 serves of fruit daily and with a wide variety, then there is no reason why you won’t be as well off as constantly consuming berries or darker fruits. The idea that darker coloured fruits have a lower glycaemic load is also a myth. Cherries for example tend to have a glycaemic load of 9, while pineapples and oranges tend to have a glycaemic load of around 6.
5. Fructose Intake
A rather contentious and topical issue at the moment is the consumption of fructose, the predominant sugar found in fruits and also in honey. The articles main reason for excluding fructose is their ability to increase glycation, a process in which a sugar molecule bonds to a protein or lipid molecule producing advanced glycation endproducts or AGEs which have been implicated in a variety of chronic diseases. While fructose has been shown to have high glycation affinity and is also mainly metabolised into triglycerides, there has been a lot of bad publicity generated for fructose due to its perceived obesogenic nature. While extremely high intakes of fructose have been shown to affect metabolic processes in the body, the levels shown in studies causing these effects are often above and beyond what most people consume.
There has also been a recent meta-analysis showing that fructose may be inappropriately blamed for its effects on the obesity epidemic. When it comes to fructose, the most important point would be to reduce high fructose corn syrup consumption as there is a major consensus of its negative health outcomes. As with most things, fructose should be consumed in moderation and should predominantly come from sources closer to nature. That is from fruits and honey. Generally speaking, in Australia, we do not use a lot of fructose in our food processing. However, our American friends may want to take note that high fructose corn syrup (HFCS) is a common ingredient in a lot of their processed foods such as soft drinks, bread, and other energy dense foods.
6. Best Time to Consume Carbs
The best time to consume carbohydrates is definitely during the period before, during and after your workouts. Consuming carbohydrates before and during your workout sessions will help to provide a quick exogenous source of fuel while consumption of carbohydrates post workout will be beneficial for recovery purposes, especially in promoting glycogen storage. The actual timing of post workout carbohydrate ingestion however is contentious at best. Post exercise insulin sensitivity has been shown to be raised anywhere from hours to even days after a single session of exercise and so consuming a carbohydrate rich meal would mean a reduction in the amount of insulin released and thus less taxing for the cells of your pancreas. In terms of recovery and anabolism, the consumption of post exercise carbohydrates and protein can be consumed anytime from immediately to an hour post exercise to maximise gains.
7. Insulin Sensitivity Supplements in High Carb Post-Workout Meals
The theory behind this would be that an increase in insulin sensitivity would reduce a dramatic rise in blood insulin levels, a common problem causing issues such as leptin resistance and increased fat storage. Considering that there is a rising proportion of individuals with diabetes, pre-diabetes and insulin resistance, using insulin sensitivity supplements may not be such a bad idea. It is important though to understand that insulin sensitivity is already raised post-workout and whether there is any additional benefit with use of insulin sensitivity supplements is yet to be researched fully.1. Mann J & Truswell AS. ‘Essentials of Human Nutrition’ Oxford University Press 2007
2. ohn L. Sievenpiper, Russell J. de Souza, Arash Mirrahimi, Matthew E. Yu, Amanda J. Carleton, Joseph Beyene, Laura Chiavaroli, Marco Di Buono, Alexandra L. Jenkins, Lawrence A. Leiter, Thomas M. S. Wolever, Cyril W. C. Kendall, David J. A. Jenkins. Effect of Fructose on Body Weight in Controlled Feeding Trials A Systematic Review and Meta-analysis. Annals of Internal Medicine, 2012; 156 (4): 291-304
3. See article on Supplement Timing - http://www.mrsupplement.com.au/supplement-timing