Glucose is a building block of life that our cells use for energy. On the other hand, fructose is poorly absorbed from the gastrointestinal tract, and almost entirely metabolized by the liver. The liver metabolizes the fructose by a process called phosphorylation, turning fructose to fat to be stored in our fat cells. According to Dr Robert Lustig, ‘There is not one biochemical reaction in your body, not one, that requires dietary fructose, not one that requires sugar. Dietary sugar is completely irrelevant to life.’
In fact, having a diet of meat, eggs, good fats, fresh fruit and vegetables could easily fulfil all your body’s glucose needs, without any additional fructose. This is because around 58% of protein and 10% of fat changed into glucose in the body!
The great thing about this is, fats and protein have corresponding hormones that coordinate with our brain to switch off our appetite when we have had our fill. Fructose on the other hand, has no such ‘off-switch’ hormone, which is why we can keep drinking fruit juice or soda by the litre. Try drinking that much full-fat yoghurt…eek, it is practically impossible!
So since we don’t actually need sugar to function, how much sugar are we meant to have? The American Heart Foundation’s 2013 recommendations advise no more than 5 teaspoons (20g) per day for women, 9 teaspoons (36g) for men and 3 teaspoons (12g) grams for children. Personally, I simply try to keep my sugar intake as low as possible. In today’s society, especially counting in those hidden sugars, I find 5 to 8 teaspoons a day to be a feasible goal to work towards.
Since we have established that fructose is the ‘baddie’, here is a list of some common sources of sugar and their fructose contents. Some of these may surprise you!
- Table sugar (sucrose) contains 50% fructose. Unfortunately, this has become our number one choice of sugar as it is so easy to purchase and even more conveniently found in every café or restaurant. If your only option is table sugar, opt for raw or brown sugar if possible as it is less refined.
- High-fructose corn syrup (HFCS) contains 55% fructose. While this is not as easily accessible to the public, it is found in almost every sweetened drink out on the market, as well as in breakfast cereals, sauces, biscuits and some bread.
- Agave contains 70-90% fructose. This is found mainly in health stores as it has a low GI. However, it is important to be careful with low GI foods, as while it can be a good thing, a manufacturer’s best way to lower GI levels is often to add fructose. Fructose is one of the lowest GI substances around, which is why chocolate spreads often have such low GI levels.
- Honey contains 40% fructose. I often call honey nature’s sweetener. It is slightly sweeter than regular sugar and less can be used to achieve the same sweetness intensity. It is also great as a humectant which means that it provides and retains moisture to a variety of dishes and may help to extend the shelf life of food. The best honey in my opinion, is raw, manuka honey, if it is available in your area.
- Maple syrup contains 35% fructose. Similar to honey, maple syrup is sweeter than regular sugar and it also contains polyphenols and other antioxidants. Not to mention the fact that it has such a delicious flavour! My favourite is Grade B maple syrup!
- Coconut and palm sugar contains 35-45% fructose. I love coconut sugar and find it to be extremely versatile. It is recognized by the Food and Agriculture Organization as one of the most sustainable sweeteners as coconut palm trees produce an average of 50 to 75 percent more sugar per acre than sugar cane. It also has a nutritional profile that includes amino acids, potassium, magnesium, zinc, iron and B vitamins.
Now, some of you may be feeling a bit confused at this point and I want to clarify that fructose as a negative is a separate entity from fruit as a whole. While some fruits are higher in fructose than others, fruit in general is fantastic and I strongly recommend everyone have at least two to three servings of fruit per day.
Our ancestors were onto something with fruit – they really are nature’s best candy! They are full of vitamins, water and fibre (which the body has an ‘off-switch’ for, so you don’t over-consume). I try to avoid dried, sweetened or preserved fruit as I find fruits are best eaten whole and raw, after a meal or as a snack.
Over the next ten weeks, we will be providing you with different recipes and food ideas to help you minimize your sugar intake. The best way to do this in my opinion is to focus on what we can eat and to fill up on those (such as healthy fats , fiber and protein).
I encourage you to join us on this journey to a healthier, better you!
In good health!