Sweet but Deadly: Protecting Our Little Livers | Grandma Kouzi
In 1972, British scientist John Yudkin published a book titled *Pure, White and Deadly*. The protagonist of that book was sugar: pure, white sugar. The protagonist of this short piece is also sugar: sweet sugar.
In this context, “sugar” refers to table sugar, confectionery, and added sugars in food. On ingredient labels, it might go by various names such as sucrose, white sugar, high-fructose corn syrup, honey, maltose, or glucose syrup.
The updated US Dietary Guidelines, released in January 2026, emphasise that “sugar is not considered part of a healthy or nutritious diet”. I agree in principle, though I have my doubts about how feasible that actually is.
1. Why We Need Sugar, and Why We Don’t
Glucose in the bloodstream is the body’s primary energy source, much like fuel in an engine. Engines run on petrol; human life runs on sugar. I have taken part in Hong Kong’s 100-kilometre trail walk and the 66-kilometre Mount Tai marathon, where sports drinks containing sugar and electrolytes are a staple at every aid station. This can easily foster a misconception—that sugar is vital, and that we need to eat it. In reality, that is not the case.
A common greeting among Chinese people is “Have you eaten?” Rice and staple foods are our most everyday source of energy, primarily consisting of starches. Starch is a high-molecular carbohydrate formed by multiple monosaccharide molecules linked by glycosidic bonds; it is a type of sugar that does not taste sweet. Composed of hundreds or thousands of polymerised glucose units, starch molecules are simply too large to bind effectively with the sweet-taste receptors on our tongues, so our taste buds cannot register them as “sweet”.
In that sense, steamed rice and mantou are sugar, as are potatoes and taro. However, this kind of sugar falls under polysaccharides (such as starch and cellulose), which belong to the broader carbohydrate family alongside monosaccharides (like glucose and fructose) and disaccharides (like sucrose and maltose).
The process of eating and digestion is essentially a series of chemical reactions that hydrolyse these polysaccharides into the monosaccharides our bodies require. The body uses enzymes as scissors to cut the “sugar chain” of starch. Before reaching the stomach, the scissors are “salivary amylase”; once passed into the small intestine, they become “pancreatic amylase”. Ultimately, the polysaccharides are broken down into their smallest units, transforming into monosaccharides that cannot be hydrolysed further and enter the bloodstream. Sugar, therefore, is a vital substance the body can produce on its own without us needing to consume it directly.
While blood sugar is indispensable to life, we have no biological need to eat sweet-tasting sugar.
II. Sugar Is Everywhere
A few years ago, while in Taiwan, someone tallied up the food aisles in supermarkets. If you were to remove pure sugar and every product containing added sugar, fewer than 20% of items would remain.
Sugar has thoroughly embedded itself in contemporary life.
All sweetened beverages, filled sweets, chocolates, and pastries are packed with sugar. Ice cream and frozen desserts are outright “sugar-fat bombs”. Ready-to-eat puddings, sweet tofu pudding, and instant milk tea are equally staggering in sugar content. Instant oatmeal and cereal bars may look healthy, but they are often just as high in sugar. Then there are the hidden sugar heavyweights: savoury snacks like potato chips, shrimp strips, and rice crackers routinely have added sugar, as do flavoured nuts and most ready-to-eat meat products, which use sugar to boost flavour.
Even some products boldly advertise themselves as “Sugar-Free XX” or “No Added Sugar XX”. But a quick glance at the ingredient list reveals the trick: the product is merely “sucrose-free”, having swapped it for high-fructose corn syrup, honey, maltose, or glucose syrup—all of which are still sugar.
Condiments are another minefield. Salad dressings are often high in both sugar and fat, making them genuine hidden sugar traps; tomato ketchup, sweet chilli sauce, barbecue sauce, instant noodle seasoning packets, and ready-to-eat soup bases almost all contain sugar. Oyster sauce might not contain any oysters, but it will certainly contain sugar. Even seasoned vinegars and dark soy sauce are sweetened—the darker the colour, the more sugar added…
3. A Lifestyle That Overworks the Liver
The most common monosaccharides are glucose and fructose, the two components of sucrose. Though they often appear together, they are almost entirely different in both structure and how the body processes them.
Glucose comes from starchy foods like grains and potatoes. It is an aldehyde sugar that can be used directly by cells throughout the body. The term “blood sugar” typically refers to blood glucose. Its metabolism relies on insulin, it carries a high glycaemic index, and excessive consumption can lead to diabetes.
Fructose, by contrast, is a ketone sugar found in fruits, honey, and corn syrup. It is roughly 1.2 to 1.7 times sweeter than sucrose. Fructose is metabolised primarily in the liver, does not require insulin, and when consumed in excess is rapidly converted into fat that accumulates in the liver, resulting in non-alcoholic fatty liver disease (NAFLD).
Although the human liver can metabolise up to 100 grams of sugar per day, the World Health Organisation recommends that adults limit their daily free sugars intake to less than 5% of total energy intake (around 25 grams). Free sugars are defined as monosaccharides (such as glucose and fructose) and disaccharides (such as sucrose or table sugar) added by manufacturers, cooks, or consumers to foods and drinks, as well as sugars naturally present in honey, syrups, fruit juices, and fruit juice concentrates.
The liver is one of the body’s most vital organs, responsible for life-sustaining metabolic processes, detoxification, bile secretion and excretion, synthesis, immune defence, nutrient storage, and blood regulation. It is not designed to serve sugar alone. Each of these functions branches into many sub-processes; metabolism alone encompasses sugar, fat, and protein breakdown. We are born with only one liver, and it must be treated with care rather than turned into a one-way street for sugar metabolism.
Yet many people push their liver to the limit every single day. A 500ml bottle of cola contains roughly 50 grams of sugar. Add in sugar-laden milk tea, the myriad “hidden sugars” in ready-to-eat supermarket snacks, the added sugar in takeout meals, and a drink or two of alcohol… and you are effectively overworking your liver daily.
Sugar’s harm does not stop at the liver. A long-term high-sugar diet causes frequent blood sugar spikes, forcing the pancreas to continuously secrete large amounts of insulin, which eventually progresses to type 2 diabetes.
Sugar also contributes to abnormal blood lipids, elevated blood pressure, vascular inflammation, and atherosclerosis, significantly increasing the risk of coronary heart disease, heart attacks, and stroke. Sugar is a key driver in the “fatty liver → diabetes → heart disease” pipeline.
IV. Why Sugar Is So Hard to Kick
Gout and fatty liver are usually thought of as adult diseases caused by alcohol consumption, so why are children who don’t drink ending up with them?
Because children in modern society are drinking a “non-intoxicating brew” almost every day – fructose.
Cases of non-alcoholic fatty liver disease are rising, affecting younger and younger children, because sweets, pastries, and drinks are everywhere, leaving kids’ livers soaking in sugary syrup from a tender age.
The 2026 US Dietary Guidelines emphasise that sugar is not considered part of a healthy or nutritious diet, stating “it is not recommended to consume any amount of added sugars or non-nutritive sweeteners, as they do not belong in a healthy or nutritious diet.” It also advises completely avoiding added sugars during infancy and toddlerhood, and recommends that children aged 5–10 consume no added sugars at all.
I agree with the stance, though I doubt its feasibility. As mentioned earlier, added sugar features in around 80% of supermarket products. Moreover, today’s children have had their reliance on sugar written into their biology from a young age, through the bliss point of sugary foods.
“People are not choosing nutrition; they are choosing a sensory experience. Sweetness is the fastest route to pleasure.”
These words come from the renowned Howard Moskowitz, a Doctor of Experimental Psychology from Harvard University. He excelled at precisely applying mathematical models and statistical methods to measure and analyse human sensory responses. His most famous achievement was discovering the “bliss point” in the 1970s – the perfect balance of sweetness, saltiness, and fat content (or crunchiness) in food. When the flavour stimulation hits just the right note, it triggers pleasure centres in the brain, making people feel like “the more they eat, the more they want, and they just can’t stop.”
Moskowitz explained it this way: “The bliss point refers to your favourite sensory experience with food, and it is primarily linked to sweetness.” Sugar and sweet foods trigger the brain to produce endorphin-like substances, creating a sense of joy and satisfaction. Once sugar levels reach a certain threshold, the bliss point is triggered – in other words, it becomes addictive.
Since the 1970s, the sweetness triggering humanity’s bliss point has increasingly come not from traditional “sucrose”, but from “fructose”.
The fructose used in processed foods comes from industrially produced corn syrup. Starch is first hydrolysed using amylase to create glucose syrup, then glucose isomerase converts some of that glucose into fructose. The world’s largest and cheapest source of starch is genetically modified corn starch from the United States. Corn syrup produced this way is unbelievably cheap.
Fructose follows a metabolic pathway similar to alcohol, primarily processed by the liver. Excessive intake leads to fat accumulation, insulin resistance, and metabolic syndrome, which is why some define it as a chronic, dose-dependent liver toxin.
Moskowitz also noted: “Sugar is not the enemy; it is a tool. The problem is not sugar itself, but the system that abuses it.” Companies like Marlboro, Coca-Cola, Pepsi, Nestlé, Kraft, and others have raced to launch highly sweetened foods, predominantly targeting children, and have carved a dependence on sweetness into the lives of generation after generation.
V. How to Break Free from Sugar?
An increasing number of people are advocating for strict abstinence from sugar. It is clearly not an essential nutrient for the human body, yet it is as harmful and addictive as drugs. The fructose mass-produced in sweet drinks is particularly detrimental to children. Sugar has been etched into the lives of generation after generation since childhood; pulling it out is far from easy.
To break free from sugar, first, refuse sugary drinks. Second, do not buy sweets or pastries for yourself, nor give them as gifts. Third, choose snacks wisely. Opt for genuinely sugar-free options: unsalted sunflower seeds, peanuts, walnuts, cashews, and pistachios are all good choices. If you can eat fresh fruit, avoid fruit-based processed products altogether.
Ingredient lists are full of traps. Beyond what has already been mentioned, watch out for aliases like trehalose, inverted sugar, maple syrup, agave syrup, and concentrated fruit juice, as well as hidden sugars like maltodextrin and dextrin, which have a glycaemic index higher than white table sugar.
Artificial sweeteners like aspartame, sucralose, acesulfame potassium, erythritol, stevia, and monk fruit extract may indeed contain no sugar, but I avoid them. I am unsure whether they are harmful, and when in doubt, I err on the side of caution. Artificial sweeteners can stimulate appetite, indirectly leading to greater calorie intake. Furthermore, a quick reminder: “zero-sugar” does not mean “sugar-free”. National standards allow a product to be labelled “zero-sugar” if it contains ≤0. 5g of sugar per 100ml.
In my next post, I will share a few recipes for sugar-free and low-sugar snacks. Using ordinary ingredients available at the supermarket, you can make healthy, sweet treats at home with your children. By making them yourself, you can strive to stay healthy amidst an environment swarming with hidden sugars.
Unless otherwise stated, all images in this article are provided by the author.
Editor: Xiao Dan