Sugar and aspartame’s impact on health

Mirthe Precision Health
10 min readJul 15, 2023


What science really says about diet coke vs regular coke

It is widely known that excess consumption of sugar can have terrible effects on our health.

Fast forward, and researchers had discovered substitutes that, while tasting very sweet, have little direct effect on our blood sugar, nor calories. The magic pill!

And many surely jumped on its wagon, with non-calorific sugar substitute being a billion dollar business, and found from anywhere such as diet cokes to chewing gum to most products labelled as ‘diet’ or ‘sugar free’ in the supermarket aisles.

Does that mean you one can all the sweet treats, as long as their sugar is replaced by sugar substitutes such as aspartame, erythritol, Splenda® etc?

But wait, weren’t aspartame and erythritol in the news lately, for causing cancer and heart attacks, respectively? So what is one to do? Go back to slurping down real coca cola or stick to diet coke? Or perhaps there is another option that includes retraining one’s taste buds to crave less sweetness, keep the above as the occasional treat, but go back to a whole foods, balanced and low sugar diet that actually nourishes our cells, without all the fuss and damage? More on that below.

Is sugar really that bad?

But let’s first look at what sugar really does to our bodies. I have done a deeper dive into this in a recent article, head back to it here if you would like to find out more, or here to listen to it on my podcast. Below is a short summary of some of the many ill health effects of sugar.

While the occasional sugary treat isn’t the issue, research suggests that sugar on a regular basis unfortunately does contribute to all sorts of ill health trajectories.

When we consume sugar, and in particular its refined and processed version, devoid of fiber and the many other nutrients of whole foods that may slow down its absorption and mitigate its effect, our blood sugar spikes, which causes a range of detrimental effects. These can range from micro-inflammation and damage to our cells in the short run, to an increased risk of high blood pressure, atherosclerosis, type 2 diabetes, weight gain and obesity, cardiovascular disease, anxiety, and even cancers, partly via a process called ‘immune escape’, in the longer term (1, 2, 3, 4, 5, 6, 7, 8, 9).

Research also suggests that a high sugar diet increases the risk of autoimmune disorders, by breaking down our immune system’s ‘self-tolerance’. Common autoimmune conditions include rheumathoid arthritis, psoriasis, inflammatory bowel disorders like Crohn’s and ulcerative colitis, and Lupus (10).

Did you know that when sugar (glucose) attaches itself to our cells, in particular the protein and fat portion, it ‘glycates’ them, creating ‘advanced glycation end-products’, also coined ‘ages’ — and that is what they do, they literally ‘age’ us from the inside out. Much like a burger placed on a grill, we ‘rust’ or ‘brown’ our own cells (11, 12).

Eating a diet high in refined sugars has further been shown to contribute to negatively impact our hunger and satiety levels. Ever heard of the term ‘hangriness’, where one is that hungry that they become unbearably angry, and ‘MUST EAT NOW’? This phenomenon has become that common that we almost accept is as being ‘normal’. However, this in fact is a sign that we are on a blood sugar roller coaster of spikes, followed by dips, that make us cranky and ravenously searching for the next sugar hit.

Not to mention that sugar lights up the same reward parts of the brain that get stimulated when consuming drugs — leading to dopamine hits in the short run, and addictive behaviour to high sugar foods in the longer run.

Excess sugar consumption has even been linked to the development of Alzheimer’s, with Alzheimer’s being coined as ‘type 3 diabetes’ in some research communities, due to its high correlation with insulin resistance (and sugar consumption).

Meh. So yes, excess sugar really is that bad!

But what about sugar substitutes?

Due to the many ill health effects of sugar consumption, a lot of research effort has gone into finding solutions. One of them seemingly being sugar substitutes.

Examples being erythritol, aspartame, stevia, sucralose (Splenda®).

These provide a sweet taste, yet little to no calories, and supposedly very little effect on blood sugar. Aspartame for example, as found in diet coke and products labelled as ‘diet’ or ‘no sugar’, while about 200 times sweeter than sugar, its calorific value, at the concentrations giving the impression of sweetness, is almost zero (13). Sucralose (found in Splenda ®) is about 600 times sweeter than regular sugar, but with seemingly no effect on blood sugar.

Wonderful, now let’s get back to slurping coke all day, eating bagels and chewing gums — but the diet version of course, you may think?

You aren’t alone in your thought process. That same reasoning is what the billion dollar industry of ‘zero sugar’ and ‘diet products’ is based on. And while there may be some benefits to substituting sugars and lowering overall sugar and caloric intake, sadly research over the past years has shed light on potential negative health outcomes of some of these substitutes.

The real facts on aspartame

In particular erythritol and aspartame have recently been put in the spotlight for their potential risks on health.

A study published earlier this year showed a connection between high blood erythritol levels and an increased risk of cardiovascular disease, including blood clotting and heart attacks (14). Our bodies actually make erythritol themselves when breaking down (healthy) foods, but in very small amounts. What this research showed that it is when we consume erythritol in excess, such as found in foods with erythritol added to it as a sweetener, these terrible side effects may occur.

Its sibling Aspartame has just been categorised as a possible carcinogen (possibly contributing to the development of cancer) Group 2B to humans. But again, like erythritol, this correlation is only there if consumed in large doses. The WHO issued a statement today (July 14th 2023) reaffirming the acceptable daily intake of 40 mg/kg body weight.

Dr Francesco Branca, Director of the Department of Nutrition and Food Safety, WHO states that ‘The assessments of aspartame have indicated that, while safety is not a major concern at the doses which are commonly used, potential effects have been described that need to be investigated by more and better studies.’

For example, with a can of diet soft drink containing 200 or 300 mg of aspartame, an adult weighing 70kg would need to consume more than 9–14 cans per day to exceed the acceptable daily intake, assuming no other intake from other food sources (15).

So while the occasional can of diet coke as a treat (or cheat, you name it whatever you’d prefer) likely won’t give you cancer, slurping down on it all day ‘to prevent weight gain’ won’t be in your favour.

And while its correlation with cancer has gained publicity in the past weeks, aspartame has also been associated with other health concerns in the past, such as

  • Mood disorders
  • Cognitive impairments
  • Headaches and migraines
  • Obesity and changes in feeding behaviour, in particular in children whose mothers were consuming a large amount.
  • Autism
  • Early start of menstruation

And what about other sugar substitues?

Non-caloric artificial sweeteners in general have been associated with changes in gut bacterial diversity with potential effects on hunger, inflammation and blood sugar control (16, 17, 18, 19).


In a study published in 2015, humans displayed an altered gut microbiome and worse blood sugar control after a week of eating the non-caloric artificial sweetener saccharin (20).


In a recent study published in 2023, mothers’ heavy sucralose (Splenda®) ingestion during pregnancy affected the newborns’ features. Newborns from mothers who intensely consumed sucralose during pregnancy were heavier and exhibited markers of metabolic changes and low-grade inflammation. However, these changes were only seen in the heavy intake group with more than 36 mg of sucralose per day (21).

As a point of reference, 1 packet of Splenda contains 12 milligrams of sucralose.

Other concerns are that the extreme sweetness of sugar substitutes can mess with our hunger signals. If real sugar create sparks in the brain’s addiction centres, sugar substitutes may be comparable to a full firework display.

Another recent study published in 2022 showed that the long-term intake of both sugar and non-caloric sugar substitutes, including aspartame, sucralose and xylitol showed increased total cholesterol, LDL cholesterol (the ‘bad type’), and triglycerides, along with significantly impaired short and long-term memory.

However, more research is needed, as there is still conflicting data to this point (22).


Often touted as the healthier option to cane sugar due to its lesser effect on blood sugar nor insulin release, fructose (fruit sugar) in its processed version may not be all that it is cracked up to be. While small amounts, as found in whole fruit, can contribute to getting ones daily dose of mineral and vitamins, excessive consumption, in particular of the highly refined high-fructose corn syrup, prevalent in many foods and beverages due to its cheap production, and high palatability (our taste buds love it), is not a great idea.

Studies show that a high fructose diet contributes to high cholesterol, in particular the ‘bad type’ LDL, triglycerides, and even insulin resistance (23).

High fructose intake has also come under scrutiny for its contribution to high uric acid levels (which is a risk factor for gout), non-alcoholic fatty liver disease, and messing with our satiety signals and hunger cues. Research suggests that eating the same meal with fructose instead of the ‘real deal’ glucose, while having less of a blood sugar spiking effect, unfortunately won’t signal satiety to our brain, keeping us craving and looking for foods shortly thereafter.

Agave syrup is often suggested as a healthy sugar alternative, but it in fact packs in a high amount of fructose, and if consumed excessively, can contribute to the mentioned problems.

If you do have a sweet tooth, what are better sugar substitutes?

I generally recommend my patients to go cold turkey for a while, to allow their taste buds (and brain activity) to reset. Once one has gone without sugar for a while, foods and drinks that previously tasted good, may now be overly sweet. This can often lead to you not even enjoying them any more!

But what if you would still like to enjoy the occasional treat? While research suggests that every blood sugar spike will have some damaging effect, our bodies can usually handle a little bit of poison.. and as with so many things in life, it is the dosage that makes the poison.

I don’t believe in ‘forcing’ my patients to cut out entire food groups (even treats and cheats) entirely, as often that just leads to a vicious cycle of feeling restricted, then falling off the wagon, then going back on that ‘diet’. Better, in my opinion, is to practise moderation, or an 80/20 approach, how I like to call it. Try and nourish your cells 80% (or better yet, 90%) of the time, and then allow yourself some treats and cheats once in a while, without feeling guilty!

If you do choose the occasional sweetness in your (dietary) life, try some of the below, as research suggests they likely are better alternatives to real sugar or the artificial sugar substitutes discussed earlier:

Real, whole fruit

Real, whole fruit contains some sweetness, but at the same time packs in fiber and nutrients like minerals, vitamins and antioxidants. Research suggests that consuming the whole fruit markedly blunts the post-meal increase in blood sugar, triglycerides and inflammation as compared to the processed version.

The dietary fiber found in the whole fruit slows down the absorption and lowers the resulting blood sugar spike (24, 25, 26).

Further research suggests that the prebiotics (fiber) found in whole fruit can stimulate the growth of beneficial bacteria in the human colon and might offer protection against advanced glycation end product formation and other ill health effects of excess blood sugar spikes (27).

Beware that tropic fruit like mangoes, bananas and pineapples pack in a lot higher sugar content compared to local varieties like berries and apples, and even those natural, whole fruits are best only consumed in small amounts, as part of a varied and balanced diet.

Having your fruit alongside some protein and fiber will also lower its effect on blood sugar, and give you more satiety. So try for a full-fat yoghurt with some berries as a dessert, after a balanced meal, instead of grabbing some grapes as a snack on their own. This will have a very different effect on your metabolism, blood sugar and health profile!

And if you are craving for something just a little sweeter as a treat, stevia and raw honey may be your best choice!


Stevia appears to be safe as shown in over 200 published studies. Studies show that it has blood sugar lowering, antioxidant effects, and may even help lower blood pressure, fatty liver, atherosclerotic damage and inflammation. It may also support our healthy gut microbiome, that balance of bacteria in the gut, needed for long term health, prevention, and blood sugar control (28).

However, still beware of its high sweetness, potentially messing with our reward and addiction centres in the brain, and as such also best only consumed in small amounts as a treat, as part of a varied and balanced whole foods diet.

Raw honey

Despite honey being fairly high in sugar, it (the raw version that is, not its processed and heat-destroyed variety found in most supermarkets!) does pack in some wonderful nutrients, that have been shown to contribute to immune health, and assist the body in fighting off infections, gastritis and more (29).

If you are looking for a little bit of sweetness here and there, this may be a better, and more nutritious treat, then other varieties.

Again, best not over consumed, and ideally combined with a varied and whole foods diet to lower its blood sugar spiking effects.

A note of caution: honey is not safe to be consumed for babies under 12 months old.

So what is the verdict re sugar substitutes?

Even though the WHO has given green light at average consumption levels, and indicate that ill health effects are likely only present at levels much higher than average (ie 10 cans of diet coke per day, etc), I generally would recommend a ‘common sense’ approach. While the occasional diet coke or chewing gum likely are absolutely fine, I would avoid excess amounts of anything that is ‘man-made’ as our bodies have evolved to work in a wonderfully balanced manner. I would act caution and reduce the excess exposure to anything that has been linked to mess with our health, and in particular that of our offspring. The risk-benefit ratio is just to high in my humble opinion.

I’d recommend sticking to a balanced, whole and real foods, unprocessed diet wherever possible, with the occasional, guilt-free treat — whether that be a real sugar cheat, or a sugar substitute.

What do you think? I’d love to know in the comment section below.



Mirthe Precision Health

Functional Medicine Practitioner. Hormones, epigenetics, health optimisation. IG/ TikTok/ Youtube/ Fb: @mirthe_precisionhealth,,