Articles – Reading Food Labels, Misguidance and Misdirection
Part I: Carbohydrates and Calories
Arguably one of the biggest mistakes people make when they go food shopping is deciding on what to buy by looking at the calorie content on the back of the label. There are just so many things wrong with this that I don’t know where to start. For the most part, the nutrition information given is fairly useless. They tell us about calorie content, macronutrient amounts, fibre and some mineral and vitamin content. However, they don’t tell you about type specific carbohydrates, the glycaemic index, the ratio of omega 3 to omega 6, the nutrient density, the phytonutrient content or how the food was manufactured, what it was fed, how it was grown etc. So in this next series of articles I’m going to try and explain all this and why it’s so important. Hopefully, it will change your attitudes to food shopping and what you put in your basket. I’m going to start of first by discussing a bit about calories and carbohydrates:
Calories/Shmalories and Amount per serving
This is one of the first ways they trick you. So you pick up a box of cereal and it says “only 120 calories per serving”. Great right? Eh no. Just look at what they consider a serving size. In the case of good old Special K, it’s usually 30g. If you have Special K in front of you right now (but I sincerely hope you don’t!!), just weigh out 30g into a bowl. It’s nothing!! A serving size for most people is probably 3 times this amount. So you’re actually getting 360 calories per serving. This obviously defeats the whole purpose of what you’re trying to do i.e. reduce calorie intake. Apart from that, focusing on the calorie content of a food is probably one of the last things you should look at. It tells you nothing about its effect on blood glucose, its protein content, its fat content or its nutrient content. 200 calories of white bread versus 200 calories of nuts have a completely different nutrient profiles. Just for a quick overview, have a look at the table below
|150 calories of Nuts||150 calories of white bread|
|Mineral||Magnesium, Calcium, Selenium||Not much|
|Vitamins||Vitamin E, Niacin||Not much|
Now, without getting into it in detail, let me just give you a quick summary of the physiological affects this would have. So you eat 150 calories of nuts, you get no blood sugar spike and very little insulin spike. This means your energy levels stay constant and your appetite is controlled. By keeping insulin low, it also means that you are not inhibiting fat metabolism, so you are able to burn more fat. The protein and fat content helps with various things from protein synthesis to cell signalling. I won’t bore you with the detail, but the protein and fat from the nuts provide amino acids, mono and polyunsaturated fats, all which have important individual functions. Then come the micronutrients, Magnesium which is used for hundreds of cellular reactions, Vitamin E which is a fat soluble vitamin with important antioxidant properties.
Now let’s look at what happens when we eat the “low fat” bread or crackers or any other refined processed type snack for that matter. As you can see from above, it is primarily made up of carbohydrate, in this case, refined carbohydrate. So the speed at which it gets converted into glucose is fast (i.e. high glycaemic index). This then raises insulin. Insulin’s main job is to store glucose, amino acids and fatty acids. It also shuts down lipolysis (i.e. fat breakdown). The snack then provides little in the way of vitamins, minerals or other beneficial micronutrients, not to mention the lack of fibre. So you’ve set yourself up to store fat and not burn it while your body receives little to help its biological function. Suffice to say that eating 150 calories of nuts is far better for you versus eating 150 calories of white bread with some “low fat” spread!
Carbohydrate (of which sugars)
This is a bit of a tricky one to explain.
So carbohydrate has 4 different classes
– Monosaccharide’s ( single molecules e.g. glucose, fructose)
– Disaccharides (2 monosaccharide’s joined together e.g. lactose, sucrose, maltose)
– Oligosaccharides ( short chains of monosaccharide’s – e.g. Fructo Oligosaccharides)
– Polysaccharides (repeating units of mono and disaccharides both linear and branched e.g. starch, cellulose).
Now, when they refer to “sugars”, that refers specifically and only to mono and disaccharides so if the food contains glucose, fructose or lactose, then these will be classified as “sugars”. The first problem to deal with here is that they don’t differentiate between “added” and naturally occurring sugars. For instance, take a look at the nutrition data on a tub of 100% full fat yoghurt. It will state something like this
|Amount per 100g|
|(of which sugars)||7.6g|
But these are not “added sugars”. These are naturally occurring sugars (i.e. lactose) that are found in milk. There is only one ingredient in these yoghurts – Milk, nothing else other than probiotic bacteria.
Then look at something like a crappy Kellogg’s cereal bar. It would state something as follows:
(Of which sugars): 7.6g
But then look at the ingredient list and you might see things like
|High Fructose Corn Syrup|
|Brown Rice Syrup|
|Evaporated Cane juice|
… all of these things are refined processed sugars that are added separately to the cereal bar. The fact that they are separate and refined (i.e. isolated molecules) means that they are absorbed much more quickly than a naturally occurring sugar wrapped up in fibre and fat. This is one of the main things that dictate the glycaemic index of the food which is a measure of how quickly it raises your blood sugar. If you were to compare the glycaemic index of full fat yoghurt versus the cereal bar, you would see that there is a significant difference (i.e. 20 for the yoghurt v 60 for the cereal bar). The cereal bar will raise your blood sugar quickly while the yoghurt won’t, despite the fact that they have the same sugar content. And this single process is what dictates almost everything about our health. Too much sugar in the blood, overworks insulin, causing dysfunctional insulin, leading to health problems ranging from obesity to cardiovascular diseases. There are literally thousands of articles, books and journals on this; here is just one of many overviews: http://www.marksdailyapple.com/diabetes/. So the bottom line is that foods that contain “added sugars” are far worse for you than naturally occurring sugars. This is not stated on label. The only way to check this is to simple read the ingredients list!
While we’re on this subject, I’ll just make a point. Like everything in the world of health and nutrition, there is never one magic bullet, nor is there ever one single culprit. Cutting out sugar and eating low GI foods won’t fix everything and make you live forever. It certainly helps, but there are several other confounding variables they need to be addressed also (which will take several more articles to explain).
So we’ve got foods like fruit, yoghurts and nuts that all contain natural sugars. An apple might contain 20g of Carbohydrates (of which sugars 20g). But again, its natural sugar embedded in the apple, wrapped in branched chain polysaccharides i.e. fibre. Thus, its glycaemic index is low (GI = 38) and it doesn’t raise your blood sugar levels quickly. While the biscuit with 20g of “added sugar” will have a high GI (~70) and raise your blood sugar level very quickly.
Finally, we’ve got foods containing starches. These are things like breads, cereals, pasta’s, rice’s and vegetables like potatoes. While these foods don’t contain added sugars or even naturally occurring sugars like fructose and lactose, they contain sugar chains. These sugar chains can in some cases easily be broken down into their individual glucose units. So a baguette or a bagel might read the following
|Amount per 100g|
|(of which sugars)||1.4g|
And this is where most people get it wrong. While there is no added sugar or actual sugar molecules like fructose and lactose present in the piece of bread to begin with, by the time it reaches the small intestines, it’s all broken down into individual sugar molecules! So if the label was presented as follows, this is how it would read
|Amount per 100g|
|(of which sugars after digestion)||40g!!|
Now, these sugars are still “natural”, so nothing has been added. However, just like I described with the apple, the other components of the food are what will determine its glycaemic index. In this case, a white piece of bread, roll, and baguette, Panini, chiabatta or anything made from white flour does not contain anything which binds the sugar such as fibre, protein or fat. Refined flour has the bran and the germ layer removed, i.e. the fibre and protein part of the grain. So, when you eat foods made of refined flour, you are essentially eating freely existing sugar (in fact the GI of a white baguette is about the same as a bag of sweets ~90). Which is why you’re probably familiar with the recommendation to eat your “wholegrains”. A wholegrain is a grain which still has its bran layer and germ layer. Therefore, it is higher in fibre and protein and will by weight contain a lower amount of carbohydrate than its refined twin. In other words, it will have a lower glycaemic index and therefore not raise your blood sugar levels quickly. So eating foods made from 100% wholegrains is much better for you than eating refined flour products. There are different grades of what’s considered to be wholegrain. The less changed the grain is from its original state the better. Wholegrain Cheerio’s (ever seen cheerio’s grown in the field??) and “Wholemeal” sliced pans are not 100% wholegrains. These foods are made from grains that have been refined and milled into their separate individual parts i.e. the bran, germ and endosperm. They are then mixed back together in varied amounts and processed into their cheerio or sliced pan. Whereas foods like oats are much less refined, they do grow in fields and they do contain all parts of the natural grain. Certain breads like Rye and Spelt are also made using 100% of the wholegrain (as long as it comes from a good source).
Another side note: Grains in general have their own issues. I’m not going to get into it here, but gluten, phytates and lectins which are present in grains have been shown to cause various health problems. This is why certain diets (e.g. Paleo) eliminate grains completely. While there is certainly plenty of evidence to support this, there are exceptions and it comes down to putting things in context. Preparation methods such as soaking and sprouting reduce the phytate and lectin contents. Certain grains have different levels of gluten and even different family species of gluten. Then there are individual differences in terms of gastrointestinal tract integrity and intolerances.
Last but not Least: Sugar Polyols
There are one other way carbohydrates can be present in our foods and that is by what are termed “polyols”. These are not technically carbohydrates are they are the hydrogenated version, which means they have an extra hydroxyl group (OH) and hence are basically sugar alcohols. They are mildly sweet tasting and are poorly digested and absorbed. This means that the calorie content is not as high as a typical carbohydrate (~2-3kcal/g) and also their insulin response is not as high. They are often added to foods to 1. Reduce the calorie and sugar content and 2. To improve the taste. So, you will see them in things like cereal bars, protein bars and also diabetic type foods. Here is a list of the typical polyols used today
Since these polyols are technically not carbohydrate, adding them to foods means that they do not count as Carbohydrate. So let’s say they added 30g of a polyol to a snack bar, it could read Carbohydrate: (0g) of which sugars (0g). So you might think, great, no carbs ! However, the 30g of polyols can still partially get converted to glucose. However, as the digestion and absorption rate is slow, only a fraction of the polyols makes it to the liver for glucose conversion. Thus their affect on blood sugar levels is small and their GI is low (typically less than 10). Does this mean they are good for you ?? Well, they are certainly better than “added/processed sugars” and most studies show that they are safe for diabetics to use. They do come in different forms, some are synthetic while others like Xylitol are natural extracts from plant fibres. Remember, they do also have a sweet taste and this property in itself can lead to sugar sensitivity problems – in other words, you will crave more sugary foods ! On top of that, the very fact that they are a refined food source will generally mean that the food product that they are used in will have other refined ingredients added such as vegetables oils and artificial sweeteners (just look at the ingredients on any protein bar that contains polyols).
In summary, judging your food on its calorie content is wrong as it does not tell you anything about the nutrient content or the physiological affect that the food has on your metabolism. The information on “calories per serving” is misguiding as it does not represent what would be considered a normal serving for most people. Figuring out the type of carbohydrates that the food consists of is crucial to determine its effect on your blood sugar and insulin levels. Added sugars wreak havoc and should be avoided at all costs. Natural sugars found in wholefoods are not harmful provided they are eaten in the appropriate quantity and you don’t have any insulin sensitivity problems. While something like an apple is low GI and contains natural sugars, a pineapple is high GI and contains natural sugars also. Hence is comes down to the fibre, protein and fat content/structure of the food. It also comes down to the quantity of food eaten and this is termed the Glycaemic Load (GL). This is a measure of the rate of carbohydrate conversion to glucose in an actual serving size of the food, unlike the Glycaemic Index, which is a measure of a specific amount of carbohydrate (usually 50g). Anyone unfamiliar with the GI or GL of foods should reference an index list (plenty of them online, just Google). Finally, beware of starches, particularly those found in refined grain foods. These foods can be just as bad as simple sugars due to the amount and speed at which they are broken down into their individual sugar units.
Take Home Points
– Don’t choose a food based on its calorie content
– Ignore “calories per serving”
– Look at the food and read the ingredient list to determine whether it contains added or natural sugars
– Avoid foods with “added sugars”
– Eating foods with natural sugars needs to be individually determined based on your needs, activity level and timing
– Learn about the glycaemic index and glycaemic load of foods
– Realise that refined starchy foods can be converted to simple sugars quickly and thus cause the same problems as “added sugars” themselves
– Foods containing Sugar Polyols should be minimised and avoided
Bottom Line: almost every time I write about food and its affect on health, it always comes back to one simple rule – eat real food as found in its most natural state !