Last week, we discussed glucose, aka blood sugar, which when elevated increases our insulin levels, which over time may for some cause both diabetes type 2, hyperinsulinemia and result in an array of chronic illness. We also discussed how when we eat table sugar (sucrose), it is made up of 50% glucose and 50% fructose. 

We discussed how when sugars arrive at the liver for processing, one of three things happen. First, the sugar can be released into the blood to be used for energy. Next, it can be either stored in the liver or sent to the muscles and stored as glycogen (a secondary source of energy). Thirdly, the liver will convert excess glucose and all fructose (yes, all fructose) into saturated fat. The vast majority of the fat that ends up in the arteries and in LDL cholesterol, is synthesised in the liver from sugars (fructose and glucose) in a process known as ‘de novo lipogenesis’ (translates into the creation of new fat). All the fat synthesised is saturated fat and most of it is palmitic acid. What makes this interesting is that palmitic acid is the fat most likely to cause cardiovascular disease (CVD). This is critical to understand, because many dietitians tell people to cut down on any food that includes palmitate acid. However, the palmitic acid in the arteries that can cause CVD, because of biologically pathways, most often originates from consumed sugar. 

This fat fact is vital to understand if you are to recognise that all those headlines you hear about the dangers of eating saturated fat are in the main misguided. The dangerous saturated fat is the one that, through de novo lipogenesis, we synthesise ourselves, to deal with sugar. It is important to understand that it is almost impossible for the fat that we eat to create very low-density lipoproteins (VLDL), which then becomes LDL. It is the synthesis of sugar, in particular fructose, that is the building block of LDL. This is basic human physiology. 

How did we get it so wrong? How did saturated fat become the devil and the little white deadly sugar escape the jury? Well, there was a series of events throughout the 1960s and 70s that led to saturated fat becoming feared, but I will share just one for now.  

An investigation recently found that in 1960 the American Sugar Industry paid Harvard researchers to produce a clinical paper stating that it was the intake of fat, not sugar, that causes CVD. Once you understand basic human physiology and de novo lipogenesis, you realise this is untrue. In fact, it is believed that over time, it is fructose that is a contributing factor to both CVD and to non-alcoholic fatty liver disease (NAFLD). 

And where does fructose come from? Table sugar, soft drinks, fruit and high fructose corn syrup.

While for more than six decades fructose has been recognised as a fat storing molecule, with so much focus on blood glucose levels, it has kind of been overlooked. Think about this logically; we have blood glucose measurements and a glycaemic index, but never fructose measurements. It’s also why people with diabetes only ever measure glucose in the blood. While glucose can be used as an energy and can be metabolised by virtually all cells in the body, fructose can only be metabolised in the liver, where it is converted by the process of de novo lipogenesis into fat. The radio silence that surrounds measuring fructose has suited the big food corporations because it’s dead cheap to produce (high fructose corn syrup HFCS is 55% fructose) and of the two sugars, it’s the one that really provides that addictive sweet taste. Plus, as food marketeers can link it to fruit, they create a perfectly innocent alibi. One more thought on all this that may really shock you, is that because fructose can’t be used as an energy source, it does not appear to dispatch the fullness hormone leptin to the brain, therefore we just eat more and more. It would seem we don’t have an off switch for fructose.

How did this happen? Well, as a species us humans might not exist at all if fructose did trigger the satiety hormone. According to research conducted by Dr Rick Johnson and the British Natural History Museum, it appears that our ability to over consume fructose and to convert it into fat, allowed humans to evolve. The story goes something like this…

Around 20 million years ago, Earth cooled. As it did, the Antarctic and to a lesser extent the Arctic began to amass ice. As a result, sea levels dropped and Africa, which was previously an island, developed land bridges with both Europe and Asia. This allowed a dozen or so species of apes to migrate to new continents. At this point, fruit was available all year round, especially the fig tree and on a diet of these fruits our ancestral primates survived. However, over the next few million years, the planet continued to cool and fruit was no longer available all year round. Many species of apes began to starve and eventually became extinct. However, one species developed a mutation of an enzyme, which altered the brains satiety receptors, making it ignore the feeling of being full when fructose was eaten. This meant the apes could gorge on fruit while it was in season, allowing them to pile on lots of weight, storing sufficient fat to survive the harsh winter months.  It is from this species of apes that millions of years latter us humans eventually evolved. 

In a podcast I recorded with Dr Robert Lustig (a leading expert on sugar) he told me,Fructose is very sweet. It’s the reason why we like sugar, and it is the reason we crave sugar. It is addictive. Fructose is the addictive component of sugar. It goes to the reward centre of the brain and activates it. We have a limited capacity to metabolise fructose. But our livers have to metabolise it because fructose does not enter any other cell. So, when you take a fructose load like Coca-Cola, it’s basically all going to your liver. And the liver gets overwhelmed because basically, it has a fixed capacity to deal with it, and if you overwhelm your liver, it doesn’t know what to do with the rest. So, the liver will turn that extra fructose into fat, and that is called ‘de novo lipogenesis’, new fat making. And that fat then has one of two fates. It can either be exported out of the liver, which in this case you have now got substrates for obesity and heart disease, or it will precipitate within the liver, and then you get fatty liver disease. And now you have liver dysfunction, insulin resistance and metabolic syndrome. You can think of fructose as the ageing compound”. 

So, fructose provides no energy whatsoever. It gets converted into fat. It is also the sugar that paradoxically has the greatest effect on insulin resistance, hyperinsulinemia and creating metabolic syndrome? Surely not? YES! Fructose, which doesn’t directly increase blood sugar or insulin, has a profoundly deep and dark side. 

And here is an interesting fact. Fructose is the only ingredient (molecule) that when consumed causes our energy to drop! Let me say that again. With all other foods as we consume them, we experience an increase in energy. That energy then reduces our appetite. Biologically speaking, the mitochondria inside our cells (effectively the power plant of our cells) converts all other foods to Adenosine triphosphate (ATP). ATP is the energy (currency if you like) that we use to fuel our cells allowing us to run, exercise, talk, think, fuel our organs etc. But to make ATP we have to burn a little fuel first to create it. A bit like we have to light a match to create a fire. But the body is clever, and it doesn’t let you burn too many matches to light the ATP fire (it’s controlled by an enzyme called phosphofructokinase). But with fructose there is no safety mechanism (it releases an enzyme called fructokinase) and to make ATP, the cell uses lots of energy, meaning our energy level falls by as much as 40 to 50%! Fructose is the only nutrient that lowers energy in our cells. As a result, in search of energy the brain keeps sending messages for us to eat more; but it’s fruitless (pardon the pun) as it’s seeking an energy boost that will effectively never arrive! It also reduces the body’s rate of metabolism to further preserve the energy stores it’s amassing.

Let’s talk about high fructose corn syrup – HFCS. It is found in the vast majority of packaged foods and beverages. It was only invented in the mid-1960’s and you can virtually track its increase in usage with the increase in rates of obesity. As in, the graph virtually looks identical. Of course, correlation does not necessarily mean causation, but with all the evidence I am demonstrating here, I would be surprised if that’s not the conclusion you draw! 

But if HCFS is so unhealthy, why is it still being used? Well, while it may be unhealthy to consume, it is super healthy for the bank balances of big food corporations.  It is super cheap to produce, much cheaper than even table sugar. It is a fluid so it’s easy to add to products. It is very sweet, and the brain loves it. Why? Back to original method of survival: our ancestral apes needed it to get through those bleak winters. Plus, as it doesn’t create energy and doesn’t initiate the satiety hormone leptin, we don’t have an off switch and eat more and more. And that my friend, is the absolute perfect ingredient to add to your produce, if you are trying to maximise sales through enabling over consumption.

According to the brilliant author of the books The Diabetes Code and The Obesity Code Dr Jason Fung (our podcast together is worthy of a listen), “fructose is even more strongly linked to obesity and diabetes than glucose”. Jason goes on to say, “fructose over feeding can increase de novo lipogenesis fivefold and replacing glucose with a calorically equal amount of fructose increases liver fat by a massive 38 percent within only 8 days. This fatty liver plays a critical role in the development of insulin resistance…. Since fatty liver and the resultant insulin resistance is a key contributor to hyperinsulinemia and obesity, this means fructose is far more dangerous than glucose”.

This now explains the Asian paradox. If we are right (and we are) that consuming too many carbohydrates such as ultra-processed foods, refined breads, pizza, rice, pasta, cereals and starchy carbs such as potatoes leads to diabetes type 2, obesity and metabolic syndrome, how do you explain that for centuries rice was the staple diet in Asia, yet most people remained lean? The answer it appears, is that glucose from these foods alone, if not massively over consumed may not cause a problem for some individuals. However, when you add to the diet daily amounts of fructose, then the body gets hit from left and right. A continuous overload of fructose in the liver directly cases insulin resistance, which is fast tracked by cells becoming insulin resistant due to a glucose overload. So now we have insulin on insulin and hyperinsulinemia, which is a root cause of many modern diseases.

Yes, in China and India, most people avoided diabetes type 2 and obesity for decades longer than in the West, but now they have themselves introduced more and more Western cusine and lifestyle patterns to their own, their levels of obesity and diabetes type 2 is sadly accelerating so fast that they have already surpassed the levels of chronic illness we are today witnessing in both America and Britain.

Let me start to bring this to a conclusion. Migrating birds eat fructose to help them fly thousands of miles between meals. Orangutangs eat fructose to fatten them. Our ancestors developed enzymes that allowed us not burn fructose as energy, but to store it as body fat as a future source of energy.

Let me state some Fructose Fats as black and white as I can:


  • Fructose in natural fruit eaten with its fibre, as nature intended, in moderation is ok.


  1. Fructose when over consumed leads DIRECTLY to insulin resistance
  2. Fructose over-consumption directly causes fatty liver disease
  3. Fructose is even more strongly linked to diabetes type 2 and obesity than glucose
  4. Fructose is used in energy storage not energy production (only the liver can metabolise it and while it’s busy doing that task, other important roles may be hampered)
  5. Fructose (especially HCFS) is found in most packaged foods and is therefore being over-consumed
  6. Fructose does little to make us feel satiety, so we are able to eat lots of it (this is why you can eat sweet desserts, even when you are stuffed from the main course)
  7. It tastes much sweeter than glucose, so our dopamine receptors often crave it, meaning for some it is addictive
  8. Fructose is the only nutrient that lowers energy
  9. Research has shown that fructose lowers our base metabolic rate

My Final thought. We evolved to eat fructose to get us through the winter. Our enzymes even muted to allow us to do so. But today, fructose is eaten all year round and in alarming quantities. This fattening molecule originally derived from nature’s candy, has ZERO nutritional benefit, and is believed to now represent 9% of total calorie input, for the average person living in our country!! 

High Fructose Corn Syrup (HFCS) is infused into so many packaged foods these days. Yet it was only invented in 1960! Funny coincidence then, as I have shared with you several times in other blogs, that the average weight of someone in the mid 1960s was 2.5 stone less than it is today!

It isn’t all bad NEWS

Dr Robert Lustig told me. “In defence of fructose in fruit, it comes with fibre. The fibre stops all of the fructose from being absorbed. The sugar is what makes it taste sweet, but it is the fibre that makes it healthy. The fibre is setting up a gel on the inside of your intestines. You need both soluble and insoluble fibres, and fruit has both. What’s happening is that you are setting up a latticework on the inside of your intestines, cellulose is setting up like a fishnet. And the soluble fibre like the pectin’s (a fibre found in fruits) and the inulin are plugging in the holes in that latticework to provide this gel, which is then reducing the rate of absorption and therefore protecting your liver. And if you don’t absorb it early, it goes further down the intestine, and your microbiome bacteria will chew it up. So even though you consumed it, you didn’t get it because your bacteria did. So, the two rules of diet which people do not understand: Protect the liver and feed the gut. Foods that do both are healthy. Those that do neither are unhealthy. Those that do one or the other are in the middle. Examples of food that do both include anything with fibre. Fruit is good, but not fruit juice. Real food works, processed food, doesn’t”.

What Robert is saying is that a small amount of fruit, which is digested alongside its fibre, that’s fine, especially when in season, but in packaged foods, table sugar, fruit juices and sodas, AVOID IT!

Customer Comment of the week

I received this lovely email from a gentleman called Chris James

You’ve been an inspiration in my house. The legendary ‘Steve Bennett’ plan is highly talked about in my town as people say to me ‘ooo you’ve lost weight’. OMAD – one meal a day. No snacking. Remove ALL sugar. No chocolate. James Cracknell said he does 100 push ups a day. So I adopted that with 100 sit ups. I know it sounds basic but it’s exercise I always claimed I never had time to do. Well I do now. And cutting out sugar was easier than I thought. In June I weighed 97kg. I now weigh 86-87kg. And feel completely different. You were the motivation I needed. So thank you for that. 

Recipe Of the Week - Tom Yum Prawn Noodle Soup

This one will for sure keep you warm through the winter months. And of course there is no fructose in sight!

  • 200g of Fibrehydrate noodles
  • 700ml of chicken stock
  • 12 de-shelled raw prawns (4 per person)
  • ½ red onion 
  • 1 tbsp of red paste 
  • 3 kaffir lime leaves
  • 1 stick of lemon grass
  • 1.5 cm piece of galangal or ginger
  • 8 button mushrooms 
  • 1 tbsp of fish sauce 
  • 3 tbsp of lime juice 
  • Handful of spinach
  • 2 tbsp of olive oil
  • Fresh chilli


Drain the noodles and set aside. In a large pan sauté the onion with olive oil for 1 minute. Add in the Thai paste on a medium hot, stirring continuously for another 1 minute. Add a good splash of chicken stock to the pan and stir to combine the chicken stock and paste together. Add the rest of the stock and bring to the boil. 

Bring the stock to a simmer and add the kaffir lime leaf, fish sauce, chilli, honey, smashed lemon grass stick and slice the ginger and galangal into the soup. Cook for 6-8 minutes to infuse the soup. Quarter the mushrooms and tomatoes and add them to the soup. Cook for another 5 minutes. 

Add the prawns. When the prawns turn pink they are cooked. Add the spinach and stir into the soup.  Lower the heat and add the noodles and lime juice. This is the time to taste the stock. Add more fish sauce if desired, or a little stevia for sweetness. 

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