About sugars and real life: intake


So, you have now read my previous posts about the addictive properties of sweetness; you know what sugars are and you know that added sugars have negative health effects, and that these effects are different when you talk about fructose or glucose, or when they are naturally present in food or added as external ingredients. Surely you also remember that if all sugars are carbohydrates, not all carbohydrates are sugars and therefore not all carbohydrates should be limited/avoided (as I too often hear in the “health conscious” community)…! Up until here, you might have found many other blogs, websites, articles and people talking, all mentioning similar concepts (let’s be fair though, this time you liked it better, right…?!?).

But one thing you might have found more difficult to read about, is how to put all these nice and healthy theories into practice… And this is one of the reasons that actually drove me towards the creation of this blog. What I am going to try with this post is indeed to help you wean off added sugars. Remember, they are addictive, it is not your fault if the more you have, the more you want; and if you put it together with the concept of a “toxic, obesogenic society” and the “Big Food” industry, whose aim is not to keep you healthy, but to sell you more food, then you would easily realize I am embarking in a David vs Goliath task…

And you will understand why you need to “wean off” sugars. It is easy to say “quit the desserts and go to the gym”, as you will have read and heard millions of times, but if it has not worked until now, I believe it is because that is just not enough… Otherwise there would probably be no obese as much as there would be no smokers nor drug addicts in the world either…

What follows is an approach that not only I have experimented on myself several years ago, when I moved form an added-sugar-rich diet to an added-sugar-moderate diet before moving to an added-sugar-limited one, with current stints of added-sugar-free nutrition (I do not reject the odd dessert, but I choose when to have one, rather being tempted into it)… And please note, it is not by chance that I have repeated the word “added” so many times… Sugars are present naturally in many foods, every fruit and vegetables, most grains and dairies and they are part of a healthy diet. What science more and more points at as a likely reason for the current epidemic in food-related diseases (often referred to as “non-communicable-diseases”) is added sugars (the “empty calories”), and that is the one thing I would invite you to and help you to try to reduce/eliminate from your diet. What that has led me to, is a lifestyle that allows me to be active and on my feet most of the day every day, working out between 10 and 15 hours a week and still have plenty of residual energy, have an impeccable cardiovascular risk factors profile and a body fat percentage at pro-athlete levels for the past 3+ years.

If the health benefits are already a big drive for me to be willing to share my knowledge and experience, several side-effects are of no secondary importance…: tasting food at a much “deeper” level (I have learnt to taste the difference between an earl grey tea, a black tea, a green tea macha or senchu…something I would challenge you to do, once you fill your cuppa with one, two or even more teaspoons of sugar!). Sure you can survive without all that, but I can promise you, the enjoyment of food once you widen the spectrum of flavors you can recognize at every bite or sip will make you repel all that processed stuff that fills aisles and aisles of supermarkets and will make you fast rather than eat the sugar-laden desserts offered in poor quality eateries and stores…; be able to control yourself and win your fight against Goliath and in doing so regain full control over your food-choices (remember, I choose when to have a dessert, I am not chosen by the dessert…). It is a multi-step approach, and as such, I will discuss them in different blog post to make it easier to digest, so to speak…:

  1. Acknowledge and measure your added-sugars intake
  2. Recognize the easy-to-avoid and easy-to-correct sugary habits, thus moving to a moderate-added-sugar diet with little effort
  3. Fill the gap with more nutrient-dense foods and improve the macronutrient profile of desserts
  4. Progressively move from a moderate-added-sugar diet to a limited-added-sugar diet (you will soon find out, the less the merrier..!)
  5. Be completely in control of your nutrition


The first step into reducing your intake of added sugars is to recognize its presence in your diet… Sounds obvious and simple, right? Wrong…! I am not just talking about the sugar you put in your coffee and tea (a good first step anyhow)… I include here the sugars you have when you drink your soft drinks and juices (and do not be fooled by the “sugar-free” theories, they might not have caloric sugars, but still have artificial sweeteners, so they keep you addicted to their products! Remember it is not the sugar but the sweetness to be addictive and promote overeating…), or eat your organic jam/marmalade or honey (again, do not be fooled by the wording, organic does not necessarily means healthy!), or have the fat-free frozen-yogurt (if you ever tried to make an ice-cream or sorbet you will know that to keep a good texture and avoid ice crystals forming in the ice-cream, you have to put either sugar or fat, and apart rare exceptions, if you reduce one you have to increase the other…!) or your diet cookies and snack bars (“diet-” is mainly referred to fat reduction, which most of time means they have increased sugars to maintain flavor). And if again, all these listed foods have a sweet flavor that can hint towards the presence of sugars, although you might have never thought about it, much more subtle but equally damaging are the sugars added to ready-made sauces (no exceptions, from ketchup to mayonnaise, mustard to barbecue sauce), packaged foods (from frozen burger patties, to nuggets and fries, to ready-made meals) and any other snacks.

I will help you at the start by providing a list of some common foods and their sugar presence here. However, what will have to follow, to have you fully in control of your diet and sugar intake, will be to read the nutritional information and ingredients list of what you buy, and understand it… If at the beginning this is a time-consuming task, it will help you understand what I mean when I say that added sugar is everywhere… And after you have learnt how to interpret the label and you have gone through the process for your most commonly used products, it will become much faster and will direct you automatically towards “healthier” options when available… Because listing all foods in this post would be never-ending, what follows is just a list of the most common products found in the supermarket, with the amount of sugars you would have with a reasonable portion (not always matching the portion-size mentioned in the nutrition label, because let’s face it, how many people eat 9 chips??!!??).

And as a reminder, the World Health Organisation has recently proposed to officially reduce the recommended daily intake of added-sugars (including honey and sugars in beverages) to 25g. As you will see, some single portion of commonly consumed foods and drinks alone exceed that amount!!!

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I hope you spent even just a couple of minutes looking at those figures… That would be enough to start thinking how much more sugars is present in processed food than you would probably think…

Can you believe, a seemingly “healthy” fruit smoothie from Caribou Coffee would land you 66g (!!!) of sugars?!? Or a frappuccino and muffin at Starbucks 67g?!?! These alone, would set you almost 3 times over the proposed daily intake of sugars from the World Health Organisation! Have a thought next time you want to meet for a chat with your friend, or browse the internet at the local coffee-shop…


As an extra comment in this post, I thought it might be useful to go through how to understand what you are actually buying and eating.

This is a supposedly healthy morning cereal, read the ingredient list!
This is a supposedly healthy morning cereal, read the ingredient list!


One commonly disregarded but in my opinion extremely useful way to rate the basic nutritional quality of processed / packed food and drinks is as simple as looking at the ingredient list. Not just WHAT is listed (remember it should be an edible product…for once probably you can confidently say that the less, the merrier!), but also in WHAT ORDER ingredients are listed (by FDA regulation, they need to be listed from the most present to the least present!).

That means that if you would like chocolate, the first ingredient should be cocoa, right? Well, not always.. Actually, very rarely that is the case! Sugar is most likely to be the most present ingredient in your chocolate bar! So it should technically be called a sugar bar…!

And in general, when sugar is listed among the first three ingredients, you can be sure that is is present in reasonably high amount. At which point you might wonder if it is really worth the purchase… If you are looking for an ice-cream, maybe you could expect that, but if you would like a tomato sauce or a soup, is that necessary?

If being present high up in the list of ingredients is an indication of likely high amount, to be even smarter you can combine that with what you can read in the nutrition facts label.

How to read the label (from http://dtc.ucsf.edu/living-with-diabetes/diet-and-nutrition/understanding-carbohydrates/counting-carbohydrates/learning-to-read-labels/)
How to read the label (from http://dtc.ucsf.edu/living-with-diabetes/diet-and-nutrition/understanding-carbohydrates/counting-carbohydrates/learning-to-read-labels/)

A product that has sugar (or any synonym, like sucrose, fructose, HFCS, High Fructose Corn Syrup, etc…) in the top ingredients and shows sugars in high amount in the nutrition facts label, can be confidently be avoided for health…!

But be careful, despite the FDA has proposed to change to regulations, there are still many tricks companies use to show what their products are not… The nutrition fact label often only reflects the amount of macronutrients in one portion, or in 100g… READ CAREFULLY, as it is likely that you are going to eat a lot more than that…! As briefly mentioned above, one serving of chips amounts to about 30g… When was the last time it took you 12 times to finish a medium bag of chips??? Or 5 times to finish a 500g tub of ice-cream? And did you know that the nutritional information displayed on a bottle of sports drink (typically 500ml) is related to 250ml of it? You will likely have to do some simple maths, and multiply the indicated amount by a factor of 2 or even 3…

So now that you have all the tools, next time you go out for a drink or to the supermarket, invest a few minutes to read the ingredient list and nutritional information of the food and drinks you regularly consume… I bet you will be surprised and in the long term, you will be happy you did… Remember, it is never too late to regain you health and you taste buds…!

If you found this post interesting, I hope you will stay tuned for what is coming up, another practical post on how to progressively reduce your sugar intake, what to expect and how to fill the nutritional gap in your diet (with what I believe are not just healthier, but also much more satisfying options…).

About sugars and (dis-)metabolism


So, if you have been trough my previous post “About sugars and addiction“, you might now be wandering why that matters… And what it means that glucose and fructose behave differently in our body… And why that matters too… Brace yourself and enjoy the ride on the next part of the post, where I hope you will find your answers (and hopefully raise more questions for my next posts)…!

Once foods enter the body (any food), they get broken down (mechanically by the teeth, chemically by enzymes and digestive juices secreted by the salivary glands, stomach, pancreas and liver and again mechanically by the stomach and intestine movements) into their smallest constituents. Guess what? All digestible carbohydrates (not the pre-biotics for example, which as you know by now, are non-digestible carbohydrates) will eventually end up in glucose, fructose or galactose. After being broken down to their smallest parts, the mono-saccharides get absorbed. Absorption requires a passage through the liver where the first major difference between glucose and fructose becomes evident (and this matters to your health!).

While glucose can in fact be metabolised both in the liver and in other tissues and is rapidly released into the bloodstream (causing release from the pancreas of the hormone insulin of which I will detail soon), fructose is almost completely metabolized in the liver. Here it goes broadly into three pathways: 1. It is used for energy by the liver (more efficiently than glucose); 2. It is converted glucose (and released into the bloodstream) or glycogen (and used as storage); 3. It is converted into fats through a process called “de novo lipogenesis” (formation of lipids from scratch…) and released as either tryglicerides (TG) or low-density lipoproteins (LDL) or kept in the liver for storage.

The diagram below shows schematically the fate of fructose once into the liver… As you will see, the numbers show the average amount that take each of the described pathway. Numbers can only be a simplistic estimation, as they depend on a number of factors, including: the person age and gender, the liver health, the amount of other nutrients absorbed in the meal, the body state (rest, activity, recovery, etc…), the general body health (insulin sensitivity, etc…), etc…


The fate of fructose in the liver
The fate of fructose in the liver


At this point I believe it is essential to reinforce one aspect of modern diets: if it was estimated that in the early part of the 20th century (forget all the paleolithic stories, no need to go that far…) we were ingesting fructose mainly from natural unrefined sources (whole fruits and vegetables) and in big part in the form of sucrose (50% fructose and 50% glucose), nowadays most fructose is ingested in its simplest form as high fructose corn syrup (in the case of the more and more average diet, consisting of little produce and much ready made meals, sweets and soft drinks…). The reason why this is relevant is that the amount of fructose the liver has to deal with has significantly increased, together with an increased speed of delivery from the intestine to the liver (due to the absence of other nutrients that slow down the absorption, thus giving time to the digestive system to deal with the workload) and a reduction in all other nutrients that in nature are associated with it (fibers, vitamins, minerals, proteins, etc…). This has been extensively proposed as one reason for the “toxicity” of fructose. High amounts of fructose in the liver (and potentially the innate or acquired inability of the liver to deal with it effectively) have in fact been linked not only to increased blood cholesterol and triglycerides (simply speaking, some fats that increase the risk of cardiovascular disease), but also to a liver condition similar to that caused by alcohol (and for that reason called non-alcoholic fat liver disease, or NAFLD). In the link page, under the “About sugars and metabolism” heading, you will find a number of scientific papers published in peer-reviewed (i.e. good quality) journals, talking about this…

The key points to understand about fructose until now then, are: 1. Fructose is only metabolized in the liver, as opposed to glucose that can be metabolized in almost every cell in the body; 2. When high doses of fructose hit the liver at a high rate (as when drinking HFCS-sweetened beverages for example), the liver capacity to deal with it can be challenged and taken past its limits. When this happens, fructose is turned into fats, potentially increasing the risk of cardiovascular disease and non-alcoholic fat liver disease. In addition, the presence of fructose will inhibit the use of already present fats (both because you are already getting energy from fructose, and because fructose can be turned into fats if needed) and if also high doses of glucose are ingested concurrently, they will end up in storage (because fructose is used at a faster rate).

And what about glucose then? Is fructose the only villain? Unfortunately not… As mentioned earlier, when glucose enters the bloodstream, the hormone insulin is released by the pancreas to help maintaining blood sugar levels within a tight range. Blood glucose is in fact a highly controlled parameter (by itself something that should make you think that nature does not want uncontrolled boood sugar levels…). If it is true that glucose is essential for the cell metabolism, high circulating amounts can have deleterious effects on the cardiovascular system (arteries walls in particular) too. When insulin is released, it allows glucose to exit the blood stream and be absorbed by the cells, where it can be used to produce energy (or be stored as glycogen). Not only by doing this insulin controls the amount of circulating glucose (essentially reducing blood glucose), but insulin also sends a satiety message to the brain, informing your body that it has now enough available energy and does not need to eat anymore. Because insulin is cosidered the hormone of energy storage (as it is mainly released in the presence of glucose and proteins in the meal), nature also made it the hormone that prevents the burning of fats as energy sources (why should you use fat if you need to reduce the amount of glucose in the blood already?). Up to this point, everything would be as nature intended… You eat a balanced meal, your body breaks down the food into its most basic constituents and absorbs them while telling your brain that it has had enough.


Metabolic fate of glucose
Metabolic fate of glucose


However, as with fructose, problems arise when the amount of glucose to be dealt with becomes too high (as it is the case with overconsumption of sugars). Constantly high amounts of glucose in the blood cause a constant release of high amounts of insulin by the pancreas. In a similar way to how you stop hearing the train passing by if you live near the railway, the cells stop responding to insulin presence when it is constantly high… This is what doctors would call insulin-resistance. Because your body needs to lower blood sugar levels somehow and does not know other ways, it causes the pancreas to release more insulin (like a baby crying louder when the exhausted parents ignore the early screams…). At this point a blood test would likely show increased blood insulin levels and you would be diagnosed with hyper-insulinaemia. At this stage you are already facing a serious issue, because food that in normal conditions would cause a minor release of insulin, now has a much amplified insulin-response. That means less fat-burning, less feeling of satiety and more fatigue (so even when you start limiting sugars intake, that might not be enough to lose fat as you were hoping…). In addition, as the word gets nastier and less pronounceable, you get closer and closer to the point of no return… Even more problems arise when despite the increased release of insulin (hyper-insulinaemia), your blood sugar levels remain high, a situation called hyper-glycaemia (even the loudest cries of the baby have no more effect on the parents, your cells). At this point the doctor will probably label you as diabetic (after confirming other signs like the increase in blood sugars after a meal or their fasting levels)… Not only your insulin levels will be constantly elevated, your blood sugar out of control and your fat stores only increasing; your body will now be under a metabolic attack and molecules related to inflammation will start spreading into your system… It seems this low-level inflammation (measured via the presence of high-sensitive C-Reaction Protein – hsCRP – in your blood) is ultimately what causes (or at least is involved with…) the number of medical conditions that are often (scientifically or anecdotally) associated with diabetes or (see next…) the Metabolic Syndrome.

If up until here increasing activity (exercising more…!) and modifying your diet (reducing sugar intake) have scientifically proven chances of bringing you back to the right path (your cells can still get back to “hearing” the presence of insulin, therefore reducing the release of it from the pancreas while still lowering your blood sugar levels to a safe range), if left ignored, the constant hyper-activity of the pancreas to produce more and more insulin will end up causing the cells in the pancreas to burn out… This is a sort of a tipping point… Your pancreas would now be unable to produce insulin, so that the only way for you to stay alive would be to inject yourself with insulin any time you have food… You would be now labelled as insulin-dependent diabetic, and your life would be changed forever…

Can it get worse? Sure it can…! If you remember the part on fructose and its role in increasing circulating fats (LDL cholesterol and triglycerides) and you consider the post on sugar addiction, good chances are that once you get to the stage of diabetes (and even worse when insulin-dependent), you are overdoing on anything sweet… And unfortunately for you, once you past the early stage (your body starts to become less sensitive to insulin – you have been labelled insulin-resistant) you do not even really need to be gorging on sweets, because even little amounts of sugars now will cause a storm-like reaction…! It might even be the case (because you are addicted, it is convenient, it is present everywhere and maybe you think it is not that bad either…) that you are also overindulging in processed foods, sweets, soft drinks and all the rest (pasta, rice, pizza, bread, crackers and most bakery products should also be on your black list by now)… That means you are probably overloading your system with both fructose (that increases circulating fats, makes you overeat by not releasing insulin and loads you with calories) and glucose (that keeps your insulin levels too high for you to burn fats and adds more calories).

You are now likely to be overweight to say the least… And guess what? High LDL cholesterol, high triglycerides and high blood sugars are already three major risk factors for cardiovascular disease… Add a large waist line (you have been adding more and more calories while burning less and less fats…) and high blood pressure (the reasons for this are less known, but likely to be at least in part related to the hardening of blood vessels caused by elevated circulating sugars and the low-grade inflammation discussed above) and you are in full-on Metabolic Syndrome… If you also recall the systemic inflammation burning you from the inside (the high-sensitve C-Reaction Protein test), you are now in the front line to suffer from cardiovascular disease… Does that not scare you? Think heart attack and stroke, that might work better…


Dis-metabolism of excessive sugar intake
Dis-metabolism of excessive sugar intake


Because the scope of my blog is not just to scare people, what I really wanted to highlight with this post (and the previous ones) is that we are ultimately in control of our body. We are the only responsible for our health and with the exception of a minority of cases, genes play only a partial role, our behaviour (the so called epi-genetic) ultimately is what brings us down the healthy or ill path.

And the reason why I felt (and I hope) that my knowledge and experience could help you is that as I read in a textbook on basic human nutrition, we live in a “toxic, obesogenic society”. I am not joking, nor exaggerating. And that is why I do not even blame people for being overweight, diabetic, having the Metabolic Syndrome or all the rest… Going to the supermarket nowadays is truly like entering a drug store. We are so surrounded by unhealthy foods (and drinks), even marketed as “healthy”, packaged in beautiful green boxes, etc… that we end up believing what they tell us… Beware of the words “organic”, “natural”, “low-fat”, just to mention some… They mean nothing in terms of health…! An organic product (certified organic) only means that its making process has followed some specific standards… A jar of jam with 60% sugars can be organic, is that healthy? Or a chocolate bar in which no more than 40% is cocoa (it leaves most of the remaining 60% to sugar…) can be organic… Even worse for “natural”… A stone is natural… Would you have that? What is not natural actually? And low-fat was the big thing during the years of the nutritional war on fats… These years are quickly becoming a thing of the past (now that we know that some fats are not just good, but even essential and that we have seen that eating “low-fat” foods made people fat…), but unfortunately the low-fat claims resist and very often hide the “high-sugar” label…

But, eventually, what is the ultimate goal of the food industry? To take care of your health or to sell you more of their stuff? Have a thought, I do not think I need to help you find the answer… What I would like to help you doing, is to make sure you know how to avoid falling into the “Big Food” trap, how to make healthy choices and to realize that you can still enjoy great food and experience delicious tastes and flavors (even more that you do now!) while maintaining a good health…

For this, my next post will be on practical tips and how to put the theory into practice (how do you reduce sugar intake?). I have come to realise that even if the theory is there, it is often not easy to know what to actually choose while at the supermarket, or in the kitchen… How much sugar is there in bread? And what is the proportion of sugars, fibers, fats and proteins? Are white bread, sourdough bread, brown bread or multi-grain bread all the same? And what about pasta? And fruits? Are all desserts equally bad? Do you think you are doing yourself good by eating cereals in the morning? Have you seen that most of them are packed with sugar? And did you know that one tablespoon of ketchup contains at least one teaspoon of sugar? This and more is what you will hopefully come to know soon, so stay tuned…!

About sugars and addiction…


If I started cutting the use of added sugars (from being a sugar-holic to reducing my intake to almost zero) in my initial attempts to follow the Zone Diet (circa 2005-2006), it was not until around 2008 that I started to become almost obsessed about avoiding them. It was before the recent witch-hunt against added sugars (at least before it got more media and social attention) and I remember reading on a news webpage something like “Sugar is more addictive than cocaine”… It obviously caught my attention, so I read on, found the link to the original scientific paper and tried to find out if it was just another big media claim or science was actually behind it… Much has been written since then and with that, much more I have been reading and learning… What follows is a quick journey into what I learnt about sugars, to try to understand why they have become the number one suspects for the obesity epidemic, why I strongly believe that cutting their intake is a necessity for health and wellbeing and possibly giving you some practical tips on how to control / reduce their intake…

I will divide the topic on sugars into several subsections (as different posts, all starting with the “About sugars and…” title line) as I realise that one single post would probably have most of you sleeping halfway through…! I hope that by going through the different sections, not only you will keep alert and interested, but also you will be able to more easily find the part you are most interested in for future reference…

Before I continue, I would like to point out a couple of things:

  1. Most of these posts will be about added sugars, which represent a very small portion of the carbohydrate family. Do not take these posts as a generalisation about carbohydrates (I will talk about different types of carbohydrates in future posts). If you are not sure about what is a sugar and what is a carbohydrate, or what is the difference between fructose and sucrose (among many others), hopefully you will know by the end…
  2. For those of you who want to do what I did, here is the link to the freely available original paper I just mentioned: Intense Sweetness Surpasses Cocaine Reward (Lenoir et al, 2007). For those who cannot be bothered, but are just curious, I will start this post with a summary of what the researchers did, and discovered..

The researchers wanted to compare the addictive effect of sweet taste (saccharine, but also sucrose in one part) and cocaine in laboratory rats. After all the preparation which ensured an appropriate learning phase (the rats knew what they were choosing, as thoroughly described in the paper), they divided around 100 rats into 3 groups (C+/S-; C-/S+; C+/S+). Rats were placed in identical cages, in which two levers were connected to two “feeding” systems. In the C+/S- group, if the rat pressed the C-lever (linked to the cocaine feeder), they would receive a cocaine dose, but nothing would happen if they pressed the S-lever (linked to the saccharine feeder). In the C-/S+ group, if the rat pressed the S-lever, they would receive a saccharine-sweetened beverage in their cage, but nothing would happen if they pressed the C-lever (no reward). The C+/S+ would receive either their cocaine dose or their sweetened beverage, according to their choice. Here is what happened:

What the rats chose
What the rats chose


The empty circles are the C+/S- group. When only the cocaine lever gave the reward, then rats ended up predominantly choosing the C-lever.

The full triangles are the C-/S+ group. When only the saccharine lever gave the reward, then rats ended up predominantly choosing the S-lever.

Now the first interesting finding in the full circles (the C+/S+ group). When the rats could choose between the cocaine and the saccharine reward, they behaved almost in the same way as if the C-lever did not give them any reward: essentially they predominantly favored saccharine over cocaine (!!!).

But then the scientists went further.

They wanted to see how cocaine-addict rats would behave when exposed to saccharine. To test this reaction, they took the rats that had previously shown preference for the C-lever in the C+/S- condition together with other rats which had been self-administering cocaine for up to three weeks. They put them in the same condition as the C+S+ condition (free choice of either cocaine or saccharine) and here is what happened…:


Cocaine to Saccharine Addiction
Cocaine to Saccharine Addiction


As you can see, after an initial period of preference for cocaine, almost all rats switched to the saccharine lever by day 10…!!! Cocaine-addict rats preferred saccharine-water to cocaine if given the exclusive choice…!!! The authors concluded their article presenting some hypothesis about the neurological pathways activated by cocaine and sweetness and how saccharine could surpass cocaine as an addictive substance.

It is important to note here that not only the experiment was on rats, so translation to humans should be done cautiously (actually many studies since then have also identified an addictive behavior of foods – sugars and fats in particular – on the human brain, please see my link page for more info…). The scientists also used saccharine (a sugar substitute, not a sugar itself) as it is much sweeter than sugars. They however reported that similar results were obtained with sucrose. In addition what I am interested in, is actually the addictive property of the sweet taste, not of the particular substance as it is the taste addiction that can go on to play a major role in human health…


If you are shocked as I was after reading about the addictive properties of sweetness (and sugars are sweet…), you will probably understand why I decided to spend much attention into understanding more about this food category. So what is a sugar? And what are carbohydrates? Are they the same? And what about the sugars in fruit? And vegetables? Why is more likely that you would crave a dessert than some broccoli? I have been surprised over the years about the lack of general knowledge about food and nutrition… After all, we make a “conscious” choice  (is it really conscious?) several times a day: what shall I eat? And despite this, very few people know the difference between proteins and carbohydrates, or if vegetables are good or bad sources of proteins, or if they are rich in sugars… If it is normal not to be a food scientist or to analyse each snack at the microscope, I hope that by the end of this post you will not only know a bit more about carbohydrates, but most importantly, you will be able to make that conscious choice a bit more consciously…

Sugars are a subclass of carbohydrates. Consider a carbohydrate (also called saccharide) a construction made of many small pieces. Each piece is only made of Carbon and Water (hence the name carbo-hydrate). If the construction has only one (mono-saccharide) or two (di-saccaride) units, it is referred as a sugar. Other carbohydrates can be made of up to 3000 single units… So, point number one: every sugar is a carbohydrate, but not every carbohydrate is a sugar…

Glucose is a sugar in its simplest form, it is one of the major sources of energy in our body and it is made of only one unit (a mono-saccharide). Like glucose, fructose and galactose are also monosaccharides and if the chemical difference among them is minimal (mainly related to the three-dimensional structure in the case of fructose and the position of one chemical link in the case of galactose), their behaviour in our body is very different. It is also important to know that galactose is barely present alone in nature, while it binds to glucose to form lactose (a di-saccharide I’m sure you have heard of…). On the other hand, fructose is commonly present naturally in fruits and plants (although, do not be fooled by the name, it does not mean that fruit only contains fructose!). Fructose is also (and very importantly when talking about diet and “un-health”) a major component of sodas and processed foods under the name of High Fructose Corn Syrup) or it also can bind to glucose (roughly 50% each) to form sucrose (another di-saccharide, the common table sugar you use for your daily dose in coffee, tea, cakes, etc…). Sucrose is also the sugar form present in fruit (as I just mentioned it is not only fructose at all!). Fructose is sweeter than glucose and its role in human nutrition has dramatically changed with the industrial production of High Fructose Corn Syrup (HFCS), a cheaper sugar than glucose or sucrose. HFCS is still made of a combination of fructose (anything up to 55%) and glucose (the remaining part) but differently than from in sucrose, in HFCS the two mono-saccardies are not chemically linked. Glucose can also be found alone in nature (in honey, partly in fruits and plant-foods) although the highest stake in the food industry nowadays is in desserts and processed foods. As discussed, it can bind to galactose (to form lactose) and to fructose (to form sucrose) or less commonly to another glucose unit to form maltose. Point number two: fructose is sweeter and its industrially manufactured form (HFCS) is cheaper than glucose. For this reason the food industry (sweetened drinks in particular) has almost completely substituted the use of sucrose or glucose with High Fructose Corn Syrup. Point three: glucose, fructose and galactose are the smallest units of carbohydrates and are assimilated differently in our body. Point number four: glucose is a constituent (with fructose) of most of the sugars commonly used in home-cooking (sucrose), while fructose alone is the most common sugar used in most industrially-processed foods (because it is cheaper and sweeter). 

When more than one or two single units of carbohydrates bind together, then oligo- and poly- saccharides are formed. These are still part of the carbohydrate family but while sugars provide essentially immediate energy to plants or animals, longer chains have generally storage (starch in plants and glycogen in animals) or structural roles (think about the hard “backbone” of celery, or just the “skeleton” of plants and flowers). To this latter category belong the well-known fibers. Because of their structure and complexity and the lack of specific enzymes in humans, fibers are not absorbed by our bodies (similarly to the subclass of starches called “resistant starch”). They therefore travel through our digestive system, attracting water to them (hence their role in softening the stools). Because we cannot digest them, fibers and resistant starches are also often recommended to dieters because they make you feel full although eventually your body does not take much energy (calories) from them. Carbohydrates that go through the digestive system without being absorbed are often left for our intestinal bacteria to digest. Because in essence they are food for our intestinal bacteria, those “undigestible” carbohydrates are often referred to as pre-biotics (they support the bacteria). PS: pre-biotics should not be confused with pro-biotics, which are live bacteria that are considered beneficial to our organism and we ingest from food (most commonly with yogurt). Point five: starches and fibres are more complex forms of carbohydrates than sugars. Point six: fibers and resistant starches are not absorbed by humans, while giving a sensation of fullness and keeping the stools soft by attracting water. Point seven: pre-biotics are eventually digested by our intestinal bacteria, which take great benefit. A healthy intestinal bacteria has been linked to a myriad of positive effects for our body, so in essence, eating pre-biotics makes you feel full, gives you little calories, spoils your intestinal bacteria which in turn give back plenty of benefits (and some gases…) .


Classification and nomenclature of common carbohydrates
Classification and nomenclature of common carbohydrates


As this series of posts need to focus on added sugars, I will now get back on track (I thought a brief digression was worth just to at least make sense of some common words often misused or not well known) with a discussion on the different effects of different types of sugars on the body and why these differences are relevant in my post “About sugars and metabolism”. This will lead to the practical post “About dietary sugars: grocery shopping and eating advice”.

Stay tuned and please feel free to comment, add more, critique, ask or just say hi…! 😉