The film that changed more minds than the dietitians did
In 2014, an Australian filmmaker called Damon Gameau spent sixty days eating the kind of “healthy” foods most people consider safe (low-fat yoghurt, fruit juice, muesli bars, cereals, sauces) and tracked what happened to his body. The film he made about it, That Sugar Movie, did something neither the dietary guidelines nor decades of GP advice had quite managed: it made a lot of people genuinely understand how much sugar is in everyday food.
More recently, the French biochemist Jessie Inchauspé, better known online as the Glucose Goddess, has done something similar for a different audience. Her framing of glucose spikes, the order in which you eat the components of a meal, and what continuous glucose monitors show non-diabetic people about their own responses has reached millions of readers and viewers. The specifics of her advice are debated within the scientific community, and some of her claims are stronger than the evidence supports. But the cultural effect is the same: she’s made the metabolic consequences of ordinary eating visible to people who weren’t going to read a paper or sit through a dietitian’s consult.
That’s worth pausing on. The science had been clear for years. Public health campaigns had been running for years. The Heart Foundation, dietitians, Cancer Council, the World Health Organization: all saying the same thing. And it took a documentary, and later a French biochemist on Instagram, to make the message land.
We don’t think this reflects badly on the medical professionals who’d been trying. It reflects something honest about being human. We’re not good at acting on information that comes to us as advice. We’re better at acting on information that surprises us: that connects something we thought was safe to something we didn’t want. The film and the Glucose Goddess both worked because they didn’t moralise. They just made the maths visible.
Most Australians have done the obvious things since. They’ve cut soft drink. They’ve taken sugar out of their tea. They’ve stopped having dessert most nights. And they’re still, on average, consuming around 60 grams of free sugars a day (about 14 teaspoons), which is above the World Health Organization’s upper limit and roughly two and a half times the level it identifies as ideal.
The reason is that most of the sugar isn’t where they cut. It’s in the food that doesn’t taste sweet. To explain why that matters, we need to walk through what the body actually does with it.
What happens when sugar arrives
When you eat sugar (whether from a teaspoon, a soft drink, a pasta sauce, or a piece of bread) it’s broken down into glucose and, depending on the source, fructose. Glucose enters the bloodstream relatively quickly, and the body has a tight target range for how much glucose should be there at any given moment. Too much causes damage. Too little causes problems too. Insulin, made by the pancreas, is the hormone whose job is to keep blood glucose inside that range.
When glucose arrives, insulin rises. Its first job is to move that glucose out of the bloodstream and into cells that can use it (primarily muscle and liver) to be burned for energy or stored as glycogen. Glycogen is short-term storage. Muscle holds some, the liver holds more, but the capacity is limited. The body’s glycogen tank is finite, and how full it is at any given moment depends on what you’ve been doing.
When the glycogen stores are full and there’s still glucose in the bloodstream, the body has a problem. It can’t leave the glucose there. So it converts the excess into fat (a process called de novo lipogenesis) and stores it. Some of that fat is stored around the body. Some of it stays in the liver itself, which is why chronic high sugar intake is a primary dietary driver of non-alcoholic fatty liver disease, now one of the most common chronic conditions in the Western world.
The fructose part of sugar takes a different path. It mostly bypasses the bloodstream and goes straight to the liver. The liver processes it, and if there’s more than the liver immediately needs, it converts it to fat too. This is why fructose-rich foods are particularly good at putting fat in the liver itself: the very thing fatty liver disease is.
So far, this is standard physiology. But there’s a piece of it that connects a lot of conventional wisdom most people hold separately, and once you see it, the whole picture changes.
The revelation most people miss
Most people hold two pieces of conventional wisdom about weight in their head, and don’t notice they’re related.
The first is that you can’t exercise yourself into weight loss. That’s broadly true: the maths of how many calories exercise actually burns versus how easy it is to eat them back in five minutes is unforgiving. Anyone who has tried to lose weight by adding gym sessions while keeping the rest of life the same has learned this the hard way.
The second is that sugar makes you gain weight. Also broadly true, for the reasons covered above.
What people miss is that these two facts are the same fact, viewed from different angles. The mechanism that connects them is glycogen.
When you exercise, especially anything moderately intense or sustained, you drain glycogen from your muscles and, to some extent, your liver. The next time you eat sugar, your body has somewhere to put it. The glucose flows into refilling those stores rather than being converted to fat. Insulin still rises, glucose still gets cleared, but the destination is different. You’re topping up the bank rather than overflowing it.
When you haven’t exercised, your glycogen stores are already full from yesterday and the day before. The bank is closed. The next sugar load, even a moderate one, even one you didn’t think of as sugar, goes straight to fat conversion. Not because the food is different, but because the body has nowhere else to put it.
This is why the most effective version of weight management is almost always both: eating less and moving more. Not because moving burns enough calories on its own to matter (it doesn’t, for most people). And not because eating less is the only thing that works (it works, but it works much better when paired with movement). They work together because movement determines where the food goes. Exercise doesn’t burn the meal you just ate. It clears the room so the next meal has somewhere to land that isn’t your liver and waistline.
For someone trying to lose weight, this changes the practical question. It’s not “how many calories did I burn this morning?” It’s “did I move enough yesterday and today that my body has somewhere to put what I’m about to eat?” A 30-minute walk, a session at the gym, a heavy day at work where you were on your feet: these don’t matter because of the calories they burned. They matter because they emptied the glycogen tank.
It also explains a frustration a lot of people have had: cutting their calories noticeably, not losing weight, and not understanding why. If you cut calories but stay sedentary, every meal still arrives at a full glycogen tank. The reduction in total energy in matters, eventually. But the metabolic signal sugar is sending (store this as fat, the muscles don’t want it) is still happening with every meal.
The reverse frustration is also explained. People who increase their exercise without changing their diet and don’t lose weight: same mechanism. They’ve emptied the tank, but they’re refilling it exactly as fast as they emptied it. The composition of the meal hasn’t changed, the amount hasn’t changed, and the same proportion that was going to fat before is still going to fat now.
The version that actually works is the one most people instinctively know: eat a bit less, and move a bit more. The reason it works isn’t the calorie maths most people think. It’s the metabolic geometry of where the food actually goes when it arrives.
Where the sugar actually is
In the 2011–12 Australian Health Survey, the most recent national-level deep analysis, 81 per cent of free sugars consumed in Australia came from what the survey calls discretionary foods: packaged and processed products, not whole foods. Soft drinks are part of that picture, but they’re not most of it. The bigger contributors are foods most people don’t think of as desserts.
A 500 ml jar of supermarket tomato pasta sauce can contain 20–30 grams of sugar, about five to eight teaspoons. A serve of sweet chilli sauce can hit five or six teaspoons. Many BBQ sauces and marinades clear 50 per cent sugar by weight. A “healthy” muesli bar is frequently 25–30 per cent sugar. Flavoured yoghurts marketed at children and parents are often 12–15 per cent. A small bottle of kombucha or “natural” iced tea can match a soft drink. Two slices of supermarket bread can contribute several grams. Even pasta sauces marketed as low-sodium or organic regularly carry significant added sugar to make them shelf-stable and palatable.
The sugar is there for understandable reasons. It improves taste, extends shelf life, balances acidity, masks bitterness, makes cheaper ingredients more appealing. From the manufacturer’s standpoint, adding sugar is the easiest way to make a product people want to buy again. From the consumer’s standpoint, it means most of the sugar in your diet is in food you didn’t choose for its sweetness.
The reason this matters clinically is that the body doesn’t care about your intent. Cutting dessert and adding a daily tomato pasta is not a net reduction. The insulin spike from a meal whose sugar is invisible to you is exactly the same as the spike from a meal whose sugar is obvious. The fat storage that follows is identical. The only difference is whether you knew it was coming.
The fruit question
This is where we want to be careful, because the popular conversation about sugar has produced some genuinely bad advice, including the idea that fruit is dangerous because it contains sugar. It isn’t. The mechanism explains why.
Whole fruit contains sugar: typically a mix of glucose, fructose, and sucrose. It also contains fibre, water, and a structural matrix of plant cells that the body has to break down to access the sugar. The fibre slows gastric emptying. The matrix slows absorption. Together, they convert what would otherwise be a rapid sugar load into something the body absorbs over a longer window, with a much smaller and slower insulin response than the equivalent amount of free sugar would produce.
A medium apple has around 10 grams of sugar, but the curve looks nothing like the curve from 10 grams of sugar in a glass of juice. The juice spikes glucose quickly and produces a sharp insulin response. The whole apple produces a much flatter curve, gives the liver time to process the fructose without overwhelming it, and arrives with vitamins, polyphenols, and fibre the juice has lost. Whole fruit is, for almost everyone, a net positive, including for people actively trying to lose weight or improve metabolic health.
A few honest caveats. Juice is not fruit, nutritionally; it’s closer to soft drink with vitamins. Smoothies sit somewhere in between, depending on how much is whole-fruit versus juice and how much fibre survives the blender. Dried fruit is concentrated sugar with the water removed, and the portion sizes most people eat are several times what a serve of fresh fruit would deliver. And people with diabetes or significant insulin resistance may need to think more carefully about quantity and timing of fruit than the general population; that’s a conversation worth having with a clinician, not a rule for everyone.
For most people, the rule is simple. Eat the fruit. Don’t drink it.
Why this isn’t another sugar guilt article
We’re not arguing that sugar is poison. It isn’t. The body is built to handle it, and small amounts as part of a varied diet aren’t doing damage. The problem isn’t sugar in any individual food. The problem is the cumulative dose most people are getting without knowing it: the difference between thinking you’ve reduced your sugar intake and actually having reduced it.
The honest position is that anyone trying to manage their weight, their liver health, or their metabolic risk is doing themselves a quiet disservice if they’ve cut the obvious sugar and ignored the rest. The cut-the-dessert version of sugar reduction often misses 70 to 80 per cent of where the sugar actually was. That’s not a small gap. It’s the difference between a strategy that works and one that doesn’t.
What to actually do
Four things make a real difference, and none of them require an extreme position on sugar.
Move before you eat, or at least the day before. The glycogen point is the most leveraged change most people can make. You don’t need to train like an athlete. You need to move enough that the next meal has somewhere to land. A walk, a short gym session, an active day: these are the difference between a meal that refills your stores and a meal that converts to fat. The order is the point: exercise creates the room, eating fills it.
Learn to read the back of the packet, not the front. The front of a package is marketing. The back is the truth. Nutrition Information Panels are legally required to list total sugars per 100g. A rough rule: under 5g per 100g is low, 5–15g is moderate, above 15g is high. For products you’d never expect to be sweet (pasta sauces, dressings, marinades, breads, cereals), anything over 5g per 100g is worth questioning. Ingredient lists are also useful. Sugar goes by many names: sucrose, glucose, fructose, dextrose, maltose, corn syrup, rice malt syrup, fruit juice concentrate, honey, agave. If more than one of these appears in the first five ingredients, the product is a sugar delivery system.
Cook the things sugar is usually hiding in. A homemade tomato sauce takes ten minutes and contains the sugar of the tomatoes. The supermarket version contains the sugar of the tomatoes plus eight more teaspoons. The same is true for marinades, dressings, and most sauces. This isn’t about cooking from scratch as a virtue; it’s about choosing where to use the ten minutes that saves you most of the hidden sugar in your week.
Treat fruit as the dessert, not as the danger. A bowl of fresh fruit after dinner, with a piece of good dark chocolate or a small portion of full-fat Greek yoghurt, is genuinely lower-sugar than most processed “low-sugar” or “low-fat” desserts. The fibre and protein blunt the insulin response. The satisfaction lasts longer. And the orientation that fruit is a treat, rather than a sin to be balanced against vegetables, is the right one.
The principle
The body handles sugar through a system that works well when sugar arrives occasionally, the muscles are ready to receive it, and the storage tank has somewhere to put it. It breaks when sugar arrives constantly, the tank stays full, and every meal is being routed to fat by default. Most Australians have cut the visible sugar and are still living the second version of that picture, not because they’re failing at self-control, but because the food environment makes it almost impossible to know how much sugar is actually in what they’re eating, and the role of exercise in determining what happens to it is barely discussed.
That’s a solvable problem. It just isn’t solved by cutting dessert. It’s solved by moving more, knowing where to look on the label, and being a little harder on the back of the packet than the front would prefer.
References used in this piece are listed in the sources section. This article does not constitute medical advice. Speak with your treating clinician about any health decisions.