Why You Need To Reduce Your Sugar Intake

it’s time to cut down on the sweet stuff

Dr Jess says: In my personal and professional opinion, sugar is the most deadly threat to our health and one of the hardest things to quit. Many people fail to realise that carbohydrates are made of long chains of sugar, and that white flour breaks down into sugar in under half an hour after we’ve eaten it! 

Look around any supermarket, and you realise that so much of the food contains white flour or sugar. The food industry has a lot of power over our health; they market foods like fruit juices, kids fruit snacks, breakfast cereals and cereal bars (all loaded with sugars) as ‘healthy’ and good for us, when the opposite is true. It is misleading and frustrating. 

Take the challenge below, to work out how many teaspoons you consume of sugar each day. While the result may be shocking, it is helpful to start looking at the carbohydrates and sugar that you eat, rather than counting calories and tracking fat. Eliminating sugar completely can be daunting, but even simple things like cooking from scratch and eating more vegetables can be positive steps to reduce your sugar consumption and take back control of your eating. 

Sugar is likely the single largest factor in rising obesity and chronic disease. Increasing levels of sugar in our diet are at least partly responsible for our increasing weight. A staggering two in three of the UK population is now overweight or obese, and there are many increasing health problems like diabetes, high blood pressure, cancer, heart disease1 and kidney disease where sugar consumption plays a contributing role. 2 As our sugar consumption increases, so does our insulin levels – insulin is the hormone produced by the pancreas to help sugar enter cells and be used by the body as energy. Unfortunately, chronically (long term) high insulin levels cause insulin resistance – i.e. the cells stop listening to insulin because there is so much of it around. This is the first step to diabetes and many other chronic diseases. 

Sugar is more addictive than heroin or cocaine.  Studies in animals and humans show that sugar produces similar behaviour to addictive drugs, including heroin and cocaine. Sugar consumption can be a harder addiction to break and resist3 than those class A drugs. This is why we can find it so hard to resist sugary foods and drinks, particularly if we eat them regularly. This supports our observation that the more sugar you eat, the more of it that you want.

We eat four times more sugar now than we did 100 years ago.4 Sugar consumption has dramatically increased over the last 100 years and even more so over the last 50 years, since the increase in processed and convenience foods and the rise of the junk food and drink industries. The best way to change your health is to go back to the way we used to prepare food from scratch. This doesn’t have to be a time-intensive, laborious process. Many meals can be prepared in less than 30 minutes. Batch cooking and homemade freezer meals like our keto cottage or shepherd’s pie can build your own range of convenience food to fit with any family and budget. Learning to cook is one of the greatest gifts you can give both your own health and that of your children.

A diet high in sugar (including fruit) increases inflammation and pain and multiplies your risk of high blood pressure, heart disease and cancer by three times. Eating higher sugar food is now well-proven to cause both an increased risk of diabetes and an increased risk of heart disease and stroke.5 Fructose (fruit and processed food sugar) in particular is shown to cause fatty liver disease.5 Cancer risk can increase anywhere up to three times in studies looking at the relationship between sugar intake and cancer. These rates are particularly high in those who regularly consume drinks with high levels of sugar.6

Sugar accelerates the ageing of our cells. Substances called advanced glycation end products (AGEs) are formed in our tissues when we have high levels of sugar in our diet. These AGEs have been associated with kidney disease, COPD and recently skin ageing. Glycation products affect our cells and a part of our DNA called the telomere, shortening which causes increased ageing of our cells.7

Eating too much sugar can also cause brain fog and memory problems. Sugar has been shown to affect brain function even in healthy people and small studies show that it causes poorer performance in brain-related tasks such as adding up and response times.8 Minimising consumption is particularly important in the older population. In a large group of 45-75-year-olds, higher sugar intake was associated with a lower ability to learn and remember words in a list.9

Excess sugar is stored as fat. Sugar and insulin levels play a critical role in weight gain. Controlling the levels of carbohydrates and sugar in our diet is likely considerably more important than looking at how much fat we eat. Low-carb diets are a successful and healthy way to maintain weight.

take the sugar challenge! 

All carbohydrates are broken down into sugar when we eat them. Processed and refined carbohydrates, like white flour, do this really rapidly – within half an hour. 

Track your eating for a day and see how much sugar you eat. Use an online search or app, like myfitnesspal to see what your total carbohydrate consumption is in grams, for an average day.  Exclude any carbs that come from vegetables (except for potatoes). Then simply divide the number of grams by five, to calculate how many teaspoons of sugar that amount is comparable to. (We exclude any carbs that come from vegetables – because they contain fibre, they break down very slowly and actually help to stabilize blood sugar levels). 

Take a look at some common foods to see how much sugar they contain:

  • 1 banana = 5tsp 
  • 1 cup of grapes = 5tsp 
  • 1 sugar doughnut = 5tsp 
  • 1/2 cup sultanas = 12tsp
  • 2 chocolate digestives = 4tsp 
  • 1 mini bag of Haribo sweets = 2.5tsp
  • 1 small glass orange juice = 6tsp
  • 1 toasted teacake = 6tsp 

Aim to try to keep your sugar levels as low as possible – under eight teaspoons daily for adults, and under six teaspoons for children. This is particularly important if you have diabetes in your family history. A huge five million people in the UK are predicted to have diabetes within the next ten years. But it isn’t just the threat of diabetes. Many chronic diseases can be improved or the risks reduced, simply by decreasing the amount of sugar that you consume. 

how do I know if my blood sugar is an issue?

There are several standard blood tests available from your doctor to help you assess your blood sugar.

HbA1c (glycosylated haemoglobin): The most common blood test to measure blood sugar levels, this test measures the amount of sugar bound to your blood cells and gives you an idea of your average blood sugar levels over the last 2-3months. A value of 48mmol*/mol (6.5%) or over is where we would diagnose diabetes (42mmol/mol or 6% suggests prediabetes), but under this level if you have symptoms (of increased thirst, increased urination, fatigue, or unexplained weight loss) it is important to also do a fasting blood glucose as this can be more accurate (if diabetes was quick in onset the average may not be correct). This test is also not considered accurate in pregnancy, young adults or children or in some ethnicities with genetic variations or conditions affecting your blood cells.

Fasting blood glucose: A blood test that is a single measure in time of where your blood sugar level after fasting (for 12 hours water only). Diabetes is considered to be a fasting sugar >7mmol/L but 2 raised values on different days are required to diagnose diabetes (without symptoms). Prediabetes is suggested >5.5mmol/L.

Glucose tolerance test: Most commonly done in pregnancy but useful whether pregnant or not this is a great test to show how you react to sugar. A fasting blood sample is taken early morning before food (fasting overnight for 12 hours, consuming only water) and then you are given a sugary drink or tablets and a blood sample is taken again at 30minutes, 60 minutes and 2 hours later. A value at 2 hours of over 7.8 mmol/L is considered to be pre-diabetes and over 11 mmol/L is diabetes.  This can be one of the best standard tests to pick up an issue with your blood sugar.

Dr Jess did a modified version of this for her patients at home during COVID-19 lockdowns which you could do too with a simple blood glucose monitor (you can buy these online). Fast for 12 hours (you can drink water) and then do a finger prick blood test (should be less than 6), eat glucose tablets (available online) to an amount of 75g of glucose and then (without eating or drinking anything but water in the meantime) repeat the finger prick test. The reading should be less than 7.8. A reading of 7.8 – 11 would suggest pre-diabetes, and greater than 11 is suggestive of diabetes). If these values are raised then see your GP for further testing. 

*Dr Jess suggests her patients aim for 35 mmol/mol HbA1c and under to have good long term health. She also encourages people to think of diabetes as a cliff, you are heading towards the edge (prediabetes >42mmol/L), you can turn away for a long time before you fall off it! If you have normal blood sugar, the tests below are extremely useful to assess your future risk, particularly if you have other health conditions. Blood sugar control is also important for improving chronic inflammation

Many functional medicine practitioners including Dr Jess do testing to identify an issue with blood sugar earlier on. By measuring fasting insulin levels and even doing an insulin tolerance test rather than a glucose tolerance test, doctors can identify instability years before diabetes develops.

Another commercial test that can show whether you are likely to have an issue with your blood sugar stability and can be extremely useful in diabetics to check their blood sugar stability is the Glycomark® test, which looks at whether your blood sugar has been raised recently and shows how stable it is.

how to eat less sugar: 

The less sugar you eat, the less you want. And likewise, the more sugar you eat, the more you want. Sugar is addictive. Unless you consciously choose to eat less sugar, you won’t break the cycle and will continue to eat more. As you eat less sugar you begin to taste more of the flavour in natural foods like vegetables and enjoy taste over sweetness.

Avoid sweet fruits. Fruit sugar is as dangerous as table sugar, if not more so, due to its fructose content. Avoid eating large quantities of dried or exotic fruits like mango and pineapple, as they are very high in sugar. Fruits that grow naturally in the UK like apples and berries are generally relatively low in sugar.

White flour breaks down very quickly to sugar. Because the process is so rapid, blood sugars soar and spike after you’ve eaten it. By reducing the amount of white flours that you eat (don’t forget things like pasta, which is made from white flour), your health will benefit and you will find your appetite for sweet things reduces. 

Cut down on processed food. By eating whole foods that have been cooked from scratch, rather than relying on ready and pre-packaged meals, you will automatically cut down your sugar. As well as seeing the improvement in your health, in many cases, it is a lot cheaper to eat this way. Our refresh programme contains a month of whole food recipes which are low in sugar and high in taste. 

Stay away from sweeteners. With the exception of pure liquid stevia, sweeteners perpetuate our sweet tooth and have been shown to raise insulin levels, increase weight gain, cause bloating and diarrhoea and alter our gut bacteria.

Do our refresh programme. 30 days of low sugar meals, high in nutrition, designed to change your relationship with food, break your addiction to sugar and reset your health. 

Consider taking Gymnema sylvestre. This Ayurvedic herb can help you cut down on sugar and reduce your cravings for sweet things. In a small study, volunteers cut their sugar consumption by 40% when taking Gymnema sylvestre lozenges daily.10 Gymnema comes in the form of a tincture (an alcoholic extract of herb) or lozenges and is generally considered safe, but consult with a doctor if you have issues with your blood sugar or diabetes or are on medication.


I thought that honey was better for me than sugar. Is this not true? 

Honey is still a form of sugar, containing the sugars fructose and glucose. It will still have the same effect on your blood sugar and insulin levels. Raw, unprocessed honey does however have some other health benefits, including antibacterial, antiviral and anti-inflammatory properties. Some medicinal kinds of honey, like Manuka, can be beneficial in small quantities for infections and for using topically to treat wounds and burns. 

I usually have cereal and fruit juice for breakfast. What can I eat instead?

The combination of cereal (high in carbohydrates, plus often added sugar) and fructose is a really high sugar, unhealthy choice, despite the myths around it being a good start to the day. Instead, try eating eggs for breakfast (if you must have bread, choose sourdough or rye bread, or look for ancient grain bread), or you could try making our healthy granola from the refresh programme. Otherwise, you could consider doing what we do, and giving intermittent fasting a try, and skip breakfast completely! 


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  2. Yuzbashian E, Asghari G, Mirmiran P, Zadeh-Vakili A, Azizi F. Sugar-sweetened beverage consumption and risk of incident chronic kidney disease: Tehran lipid and glucose study Nephrology (Carlton). 2016 Jul;21(7):608-16. doi: 10.1111/nep.12646. PMID: 26439668.
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  4. Average Person Consumes 300% more Sugar Daily than ‘Recommended’
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  7. Nguyen HP, Katta R..Sugar Sag: Glycation and the Role of Diet in Aging Skin Skin Therapy Lett. 2015 Nov;20(6):1-5. PMID: 27224842
  8. Ginieis R, Franz EA, Oey I, Peng M. The “sweet” effect: Comparative assessments of dietary sugars on cognitive performance Physiol Behav. 2018 Feb 1;184:242-247. doi: 10.1016/j.physbeh.2017.12.010. Epub 2017 Dec 7. PMID: 29225094.
  9. Ye X, Gao X, Scott T, Tucker KL.Habitual sugar intake and cognitive function among middle-aged and older Puerto Ricans without diabetes Br J Nutr. 2011 Nov;106(9):1423-32. doi: 10.1017/S0007114511001760. Epub 2011 Jun 1. PMID: 21736803; PMCID: PMC4876724.
  10. Stice E, Yokum S, Gau JM. Gymnemic acids lozenge reduces short-term consumption of high-sugar food: A placebo controlled experiment J Psychopharmacol. 2017 Nov;31(11):1496-1502. doi: 10.1177/0269881117728541. Epub 2017 Sep 25. PMID: 28944714.

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