Forty-one children with obesity, all used to a lot of sugar, had it taken off their plates for nine days. Their meals were cooked for them with the same calories as before, and starch stood in for the sugar. On the tenth day the fat in their livers had fallen by almost half.
Nine days. That is how quickly a body answers when the sugar goes, and it's the reason this is worth our effort. Sugar is in the morning cup, the favourite snack, the pasta sauce and the bread, and it's easy to eat far more than we think.
What counts as sugar
Sugar's name began as a description. It goes back through Arabic and Persian to the Sanskrit śarkarā, grit or gravel: a word for the crystals.
For most of history it was rare. Sugar was a luxury in Europe until the early 1800s, when sugar made from beet brought the price down. In Britain most of it went into tea at first.
The sugar to cut is the kind that has been added, plus a few that sound innocent. The World Health Organization's count of "free sugars" takes in table sugar, honey, syrups, fruit juice and juice concentrate. The sugar inside a whole piece of fruit, or in plain milk, is left out of it.
How much is too much? The WHO suggests keeping it to about 25 grams a day, roughly six teaspoons. One can of cola holds about 39.
For children the ceiling is lower still. In Britain it is 19 grams a day at ages four to six, about five sugar cubes, and 24 grams at seven to ten. Sugary drinks, the NHS says, "have no place in a child's daily diet". For children of four and under, its advice is to avoid added sugar and sweeteners altogether, which takes in honey, syrups, juice and smoothies. Whole fruit is fine. And no honey of any kind before a first birthday, because it can carry bacteria that cause infant botulism.
Whole fruit stays on the table. Among 187,382 health workers followed for years, whole fruit went with slightly less diabetes, and blueberries with 26% less for every three servings a week. The same amount of fruit juice went with 8% more.
It hides well. A tablespoon of ketchup carries about 4 grams, a teaspoon of sugar. Of 85,451 packaged foods sold in the United States, 74% had a sweetener with calories added. tells the story of how it got there.
Ten things that get better
1. Your weight
In tests where adults ate as much as they liked, those who cut back on sugar ended up about 0.8 kg lighter, and those who added sugar gained a similar amount. The reason is plain: sugar makes it easy to eat more. When sugar was swapped for other carbohydrate at the same calories, weight stayed put.
2. Your risk of diabetes
Across 175 countries, every extra 150 calories of sugar per person per day, about one can of soda, went with 1.1% more diabetes. That held after obesity, total calories and other foods were taken into account, and no other food showed the same pattern.
3. Your heart
Among 11,733 American adults followed for about fifteen years, those who got 10 to 25% of their calories from added sugar were 30% more likely to die of heart disease than those who stayed under 10%. At 25% and above, the risk was nearly three times as high.
Part of the route runs through the blood. Across 39 tests, eating more sugar raised triglycerides, a blood fat, along with total and LDL cholesterol, and the effect was clearest where weight was held steady. Blood pressure went the same way: in tests that ran eight weeks or longer, more sugar raised it by about 7 points on the top number and 6 on the bottom.
The warning is older than it looks. In 1972 John Yudkin, in Britain, published Pure, White and Deadly, an early book-length warning that sugar was behind obesity and heart disease. The sugar industry and his rivals ridiculed him, and his view came to be accepted years later.
4. Your teeth
Sugar feeds the bacteria in our mouths, and their acid eats the enamel. Of 55 sets of findings on sugar and tooth decay, 42 of the 50 in children and all 5 in adults found the link. Decay was lower wherever free sugar stayed under a tenth of the day's calories.
Whole fruit is kinder to teeth than its sugar suggests, because the sugar is held inside the fruit's structure. Juicing and blending set it free, which is why juice and smoothies count as free sugar. Dried fruit is on the same list of things to keep to mealtimes.
5. Inflammation
Twenty-nine healthy young men drank sweetened drinks every day for three weeks at a time, in small to moderate amounts. After each spell, a blood marker of inflammation was up by 60 to 109%.
6. Your liver
Fructose, half of every grain of table sugar, is handled by the liver, and the surplus is turned into fat. That is what the nine days showed. The children's liver fat fell from about 7% to under 4%, and the fat packed around their organs shrank as well.
7. Your cravings
Our taste adjusts. People who cut their sugar by 40% for three months came to rate the same pudding about 40% sweeter than a comparison group did. Less became enough.
8. Your mood
The sugar high is a myth. Across 31 tests and 1,259 people, sugar and other carbohydrates lifted no part of mood at any point after eating, and within the first hour they left people more tired and less alert.
Over the longer run it's no kinder. Among British civil servants, the men who ate the most sugar from sweet foods and drinks were 23% more likely to develop anxiety or depression over the next five years.
Sleep joins in. Twenty-six adults spent nights in a sleep lab, and on the day they chose their own food, those who ate more sugar woke more often in the night.
9. Your skin
Sugar in the blood sticks to proteins, including the collagen that keeps skin firm. Spots respond too. Forty-three young men with acne spent twelve weeks on either a diet low in fast carbohydrate or their usual one. The low group's spots fell by about twice as much, and they lost some weight along the way.
10. Your nutrients
Sweet foods crowd out better ones. In a national survey of American diets, nutrient intake dropped with every step up in added sugar, and vitamins A, C and E and magnesium were the ones most likely to fall short.
The "healthier" sweeteners, one by one
This is where the shelves mislead us, so we'll go slowly.
Honey, maple syrup, coconut sugar and date sugar are sugar. They taste lovely and they come from a tree, a palm or a hive, and the body treats them as what they are. Coconut sugar is 70 to 79% the same molecule as table sugar, and brown sugar is 95%, with a little molasses for colour. Honey is fructose and glucose, about as sweet as sugar, spoon for spoon. When 55 adults ate the same amount of honey, table sugar or high-fructose corn syrup for two weeks each, blood sugar, blood fats and inflammation responded the same way to all three.
Agave is mostly fructose. Blue agave syrup is 56% fructose, which is why it barely moves blood sugar on a meter and why it lands on the liver.
Stevia and monk fruit have no calories. Stevia's sweet compounds are 50 to 300 times sweeter than sugar, and our bodies leave them undigested. The Guaraní people of Paraguay and Brazil used the plant for centuries and called it ka'a he'ẽ, "sweet herb". So far they are the swap with the least against it. The World Health Organization still advises against relying on sugar-free sweeteners to control weight, having found no long-term benefit for body fat.
The sweeteners in diet products are not inert either. When 120 healthy adults took sachets of saccharin, sucralose, aspartame or stevia for two weeks, saccharin and sucralose worsened their blood sugar response, and all four changed their gut bacteria. Aspartame made headlines of its own in 2023, when the WHO's cancer agency classed it as "possibly carcinogenic to humans" on limited evidence, and its food-additives committee left the safe daily limit where it was. Saccharin, the oldest of them, was an accident: in 1879 a chemist working on coal tar noticed a sweet taste on his hand one evening and traced it to the compound he had handled that day.
Erythritol and xylitol deserve caution. In three groups of people being checked for heart trouble, those with the most erythritol in their blood were about twice as likely to have a heart attack or a stroke, or to die, over the next three years. In the lab it made blood platelets quicker to clot, and after one sweetened drink, volunteers' blood levels stayed high for more than two days. The same team found the same pattern with xylitol. Our bodies make a little of both, so the blood level is an imperfect guide to what was eaten, and the finding is a warning more than a verdict.
Allulose is the newest name, and the least tested. It is a rare sugar about 70% as sweet as table sugar with about a tenth of the calories, and American labels may leave it out of the sugar count. There is little to go on yet about years of use, and in quantity it brings wind and diarrhoea.
Xylitol is named from the Greek xylon, wood, because it can be drawn from birch, and it is sold as "birch sugar". Its good name comes from teeth, and even there the evidence is thin: some weak support for toothpaste that contains it, and too little to say for gum or sweets. Xylitol products are also known for bloating, wind and loose stools. One more thing if you share your home with a dog. Xylitol is poisonous to them.
If you have to have something sweet
The best sweetener is none. The WHO's own advice is to "reduce the sweetness of the diet altogether", and the surest way is to change what's on the plate so that sugar has nowhere to hide: meat, fish, eggs, vegetables. People who eat low-carb, keto or carnivore get there by default, which is part of why those ways of eating quiet a sweet tooth. Give it three months and taste follows.
Life has birthdays in it, though. When something has to be sweet, this is the order we'd reach for things in.
Whole fruit first. Then stevia or monk fruit, the two with the least against them so far. A bottle of is the easy way to use it in a drink. Then a little honey or maple syrup for the flavour, counted as the sugar it is. Agave, erythritol and xylitol stay on the shelf, and allulose can wait until more is known.
That order is for grown-ups. The under-fives get the fruit and nothing else from it.
Be careful if you take insulin or tablets that lower blood sugar, because eating far less sugar and starch can drop it too low; have your medicine reviewed before you make a big change.
How to cut back
Start with what we drink, because a single can holds more than a day's worth and a drink is the easiest thing to change. If it's the fizz you'd miss, a gives you that without the sugar.
If your sugar came in cola or energy drinks, expect a headache at first. That is the caffeine leaving, and headache is the best-known sign of caffeine withdrawal. Then read labels for a week, just to see. Sugar goes by many names there, and the commonest are corn syrup, sorghum, cane sugar, high-fructose corn syrup and fruit juice concentrate. For a five-second check, find "of which sugars" per 100 grams: more than 22.5 is high, and 5 or less is low.
Shrink the sweetness as well as swapping it. A slow step down gives taste the time to follow.
A whole country has tried it. A year after Britain taxed sugary soft drinks, households were buying the same volume of soft drinks with a tenth less sugar in them, about 30 grams a week. Less sweet, and nobody stopped buying.
Nine days
Those children changed nothing but the sugar, and nine days later their livers showed it. None of us needs to be perfect to get the same help.
Pick the sweetest thing you have every day, and leave it out for nine days.
Is most of your sugar in a glass? The Hidden Cost of Your Daily Sugary Drink — what one sweet drink a day does, from your teeth to your liver, and how to stop.
Still reaching for it every afternoon? The Hidden Science of Sugar Cravings — where a craving comes from, and ten ways to quiet it.
Know someone who swapped sugar for honey and thinks the job is done? Send them this, kindly.
Disclaimer: This article is general information. For advice about your own health, talk to a qualified health professional. If your mood has been low for weeks or you're having thoughts of harming yourself, reach out for help today.
Affiliate Disclosure: This article contains affiliate links. As an Amazon Associate, All For Life earns from qualifying purchases, at no extra cost to you. We only link to products we would recommend without the commission.
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