Is Sugar Really As Bad As They Say It Is?
If you pay much attention to public messaging around nutrition, it’s pretty safe to say that sugar is enemy number one right now. It’s being blamed for diabetes, obesity, and a host of other health issues, with reasoning centring around its ability to spike insulin, be stored as fat, and cause addictions.
But is any of it true? Let’s take a look, starting out with the whole obesity thing.
A few weeks back I wrote an article on how fat loss and gain actually works – you can check that out here and if you haven’t read it, please quickly go and check it out before continuing because what I say here is just a brief version of what I said over there.
You’ve likely heard the idea of calorie balance dictating weight loss and gain; basically, if you consume more energy than you expend then weight gain will happen because that energy can’t go anywhere and so needs to be stored as something, usually body fat.
Well, sugar doesn’t circumvent that whole thing.
Your body expends energy during the day to stay alive, to move around, and to do all the cool things it does, and it gets that energy from food. It’s a pretty neat system. If you don’t put enough energy into the system it takes some from its stores – primarily glycogen, which is your body’s stored carbohydrate, and body fat, and so it’s able to keep going. If you then put in more than you need over a certain amount of time then the excess is stored in those same stores for later use. Eating a highly processed food doesn’t defy this, and so in order for that sugary something to cause fat gain it needs to lead to a calorie surplus.
But what about insulin spikes? I hear you ask…let’s talk about what happens when you eat sugar.
Sucrose, table sugar, is comprised of two smaller sugars called glucose and fructose. Glucose is also what makes up starch, the carbohydrate present in potatoes and other vegetables, and fructose is the ‘fruit sugar’ found in, you guessed it, fruit and vegetables. When these two combine they create the crystalline sugar we use in baking and on our cereal. Once you eat sucrose it travels through your digestive system to the small intestine where it meets special enzymes that can cleave it in two, leaving the two simpler molecules able to be absorbed into the blood.
Their first port of call is the liver, to which they are directed via a specific portal vein, and when they get there almost all of the fructose is absorbed – indeed, fructose doesn’t appear in the rest of the body for all intents and purposes. This is either used for the liver’s own needs, or it’s converted into glucose which is then either stored as liver glycogen, or it’s dumped into the blood circulation.
Note that at this point all your body knows is that a lot of glucose has been dumped in the blood. It doesn’t know if that came from Haribo or butternut squash – the glucose is identical and treated the same. This is not to say that the latter isn’t usually the better option due to all of the other useful things contained in the food, but it is to say that your body doesn’t care what foods you eat, only about the nutrients in them, and when it comes to sugar, it’s all much of a muchness.
When your blood sugar rises above the level at which it should be maintained, the hormone insulin is secreted from beta cells in your pancreas to facilitate its storage. This hormone activates proteins within the cells of your liver and muscles that allow the glucose to be absorbed and either used or stored as more glycogen for later. Note that I didn’t say it’s stored in fat cells – that was on purpose.
Sugar cannot meaningfully be stored as body fat in human beings. It can in rats, but not in humans outside of COLOSSAL overeating over a long period of time – overeating only ever seen in laboratory studies, even in obese people
Once the glucose is all stored, blood sugar starts to drop, and so another hormone called glucagon is released from the alpha cells of the pancreas. This goes to the liver, where it breaks down the stored glycogen in order to maintain blood sugar levels, effectively keeping the brain fuelled.
That’s it. That’s all an insulin spike is – it’s a necessary reaction to elevated nutrient levels in the blood which allows those nutrients to be stored where they should be. Sure it stores things, but it can only store what is there, and then that stuff is removed from stores when needed. Where people get concerned is when they hear that an insulin spike prevents fat loss, because that is strictly speaking true – while insulin is elevated things are being stored, and so they can’t be broken down.
But that only occurs during the time that insulin levels are elevated. Once it’s done its job, insulin levels fall again and fat loss can resume – the only way you could avoid this isn’t to stop eating sugar, it’s to stop eating altogether!
(Well, you could drink oil as that’s not insulinogenic, but I don’t think that’s going to happen)
And the only time where the persistent insulin spikes cause fat to be stored and not released….is when you are overeating. Sugar may cause a larger initial insulin spike than an equivalent amount of other carbohydrates, but that’s only because it’s absorbed a little quicker and so stored quicker – meaning the initial amount is larger – the total amount of insulin needed to store 100g of carbohydrate is the same regardless of whether it’s from sugar or potato, and more importantly it doesn’t even matter.
Indeed, I’d be happy to say for the record that if you don’t have diabetes, you don’t need to worry about insulin at all!
And on that topic, doesn’t sugar cause diabetes? The answer is no.
Type 2 diabetes (the one that is usually lifestyle related) is caused by a number of things including being inactive and eating a poor diet, but perhaps the single greatest factor is abdominal obesity – fat stored around your organs – and in a specific circumstance sugar CAN contribute to that.
Remember when I said that the fructose is taken by the liver and more or less kept? That fructose is stored as glycogen because it can’t be released into the blood, then the glycogen is broken down again when needed (in the form of glucose) later. Now, if you never need to break down your liver glycogen because you’re maintaining your blood glucose by eating too many overall calories (you eat, your body only stores some because there’s just so much of it, then you eat again, etc) then what can happen is that your liver can start converting some of the excess carbohydrates into organ fat, and this can lead to non-alcoholic fatty liver disease – a really common comorbidity with obesity. This means that if you’re overeating, the sugar you’re eating can contribute to your diabetes risk – but the problem here isn’t the sugar, it’s the overeating in the first place leading to dysregulation of your body’s ability to actually use sugar properly!
So where are we now?
- Sugar can only cause fat gain if you overeat
- Sugar causes insulin spikes, but so do all carbohydrate foods, and those don’t really matter anyway (indeed without insulin spikes you’d be in big trouble)!
- Sugar doesn’t cause diabetes
And is it addictive? Well, if you think you’re addicted to sugar, try this test:
- Get a bowl
- Fill it with white sugar
- Get a spoon
- Eat all of it
After the second mouthful, you’ll notice you’re not enjoying it all that much
Sugar isn’t addictive, foods that contain sugar, fat, and usually salt are just very, very tasty. That can help you develop less-than-useful habits which can lead to feelings of poor impulse control around food, and this can definitely contribute to your difficulty maintaining a healthy weight. What doesn’t help is that these foods usually contain a lot of calories!
But that’s not the sugar’s fault, it’s the diet as a whole. Sure, if you cut out added sugar you’ll probably end up eating a better diet, but that’s because you’d be eating more nutritious foods and likely fewer calories, not because you cut out sugar.
And that means that if you DO eat sugar, in the context of a generally healthy diet, it doesn’t matter.
In fact, having a little sugar here and there is probably good for your psychological wellbeing, too!