Sugar, sugar everywhere

When I was diagnosed with advanced heart disease, I decided to change my lifestyle to see if I could arrest the progress of the disease. Amongst the changes I undertook, I eliminated readily absorbable carbohydrates and seed oils from what I consumed.

You may remember that carbohydrates are one of the three macro-nutrients used by our body. Readily absorbed carbohydrates (sugars and starches) can be harmful because they are easily broken down in our intestines into glucose. High amounts of glucose in our blood can in turn be harmful because it causes our body to generate high amounts of insulin to maintain a healthy level of blood glucose. Long-term exposure to high levels of glucose in our blood results in long-term high levels of insulin production. This can lead to a condition called insulin resistance which may have caused the negative effects on my heart and circulatory system.

One of the challenges in my approach to nutrition has been to understand just how much glucose I may be exposed to because of my choices of food. I’ve found the infographics produced by Dr. David Unwin very useful in this regard.

Who is Dr. David Unwin?

Dr. David Unwin, MD, is a general practitioner based in the northwest of England. He is best known for pioneering a low-dietary-carbohydrate approach to the treatment of type-2 diabetes. Through the years, Dr. Unwin has been highly recognized for his work in his field.

“By the end of the study, 51% of their patients had maintained reversal of type-2 diabetes by changing what they ate.”

What has he achieved?

In January, 2023, Dr. Unwin and colleagues published the results of their work in the British Medical Journal Nutrition, Prevention & Health.

The authors examined a group of 186 type-2 diabetes patients at their medical practice over a period that averaged just under three years. Within the first year of the study, the team of doctors found that 77% of patients following a low carbohydrate dietary regime were able to reverse their disease. By the end of the study, 51% of their patients had maintained reversal of type-2 diabetes by changing what they ate.

This work was reported in British newspapers at the time.

What are glycaemic index and glycaemic load?

Before we look at Dr. Unwin’s graphics, we need to understand the concepts of glycaemic index (GI) and glycaemic load (GL). Glycaemic index is a concept often used elsewhere in the literature to understand how carbohydrates (sugar and starches) can affect blood glucose.

Different carbohydrates are digested and absorbed by our bodies at different rates. GI is used to describe how quickly each carbohydrate-based food and drink can make blood glucose levels rise after consumption. GI can also be used to rank food and drink depending on whether they raise blood glucose levels quickly, moderately, or slowly. GI ranges from 0 to 100. Glucose which is absorbed quickly has a GI of 100. Slowly absorbed carbohydrates have a low GI score (55 or below).

GL combines GI plus the amount of absorbable carbohydrate (sugar or starch) contained in a particular food. Dr. Unwin expresses GL as teaspoons of table sugar (something we can all readily understand).

As an example, he compares bananas and watermelons with a GI of 62 and 80, respectively. With the higher GI, we’d expect watermelons to have a more immediate effect on our blood sugar. However, watermelons are mostly water and contain much less carbohydrate than bananas for the same weight of fruit. Once GI and GL are both taken into consideration, we see that bananas will result in more than a three-fold greater impact on blood glucose than watermelons.

Dr. Unwin’s Infographics

Dr. Unwin’s infographics help me to visualize the blood glucose effects of eating various types of carbohydrate. These charts are published by the Public Health Charity, started by Dr. Unwin.

There are 10 pre-prepared infographics showing the number of teaspoons of table sugar equivalents contained in different types of food. Nine of these cover different chocolates, breads, breakfast cereals, vegetarian options, a common breakfast, common foods, fruits, a comparison of fruits and vegetables, and white/brown/green foods. The final infographic compares the teaspoons of table sugar equivalents contained in foods with natural sugars, foods with added sugar and starchy foods that will be converted to glucose by our bodies.

“…a breakfast consisting of bran flakes, brown bread toast, milk, and apple juice contains the equivalent of 16 teaspoons of table sugar. This is without things like sugar in tea or coffee or jams and marmalade.”

Using the infographics

Use tables as presented

The easiest option is simply to use the infographics as presented. I found the Common Breakfast data quite interesting, for example. This shows that a breakfast consisting of bran flakes, brown bread toast, milk, and apple juice contains the equivalent of 16 teaspoons of table sugar. This is without things like sugar in tea or coffee or jams and marmalade.

Understand effects of food processing - compare data from different tables

I find them really useful when combining information from different infographics. For example, I don’t drink fruit juices because I don’t want to spike my blood glucose and insulin. However, I do regularly eat whole apples because the apple pulp slows the absorption of the sugar contained within. We can see the difference by comparing the Fruit and Veg with the Common Breakfast infographics. From these we see that an apple contains the equivalent of two teaspoons of table sugar but the apple juice contains nine (I’m rounding to whole numbers without decimal places).

Understand effects of lifestyle - compare data from different tables

To do this, I’ve compared Dr. Unwin’s Common Foods table with comparative data on foods that I eat. I explain how I did this below.

Table 1 shows that switching from a common diet, I have substantially reduced my daily exposure to sugars and starches. The ingredients I used to eat contained the equivalent of 50 teaspoons of table sugar. The ingredients I eat now contain almost an order of magnitude less in a range of 6-12. Bear in mind that this calculation does not consider things like the number of meals per day.

By eliminating sugars and starches, I have reduced my long-term blood sugar levels (confirmed with a continuous glucose monitor), my long term insulin levels, my chance of developing insulin resistance, and have increased the chance of slowing progress of my heart disease.

Table 1. Comparing a range of common foods I used to eat to those I eat now

He provides data on the foods I eat in his tables on Vegetarian, Common Foods, Fruits, and Fruits and Vegetables. For most of the foods that I eat he hasn’t provided individual values but he has provided a group amount of 0.2 teaspoons of table sugar per ingredient. I applied the value of 0.2 to each of the foods that he lists that are foods I eat. There are 17 of those and 17 multiplied by 0.2 is 3 (rounded). To three I add 1 for strawberries and 2 for apples. That gives me a total of 6 teaspoons listed in Table 1 below. I derived an upper limit of 12 teaspoons by taking a conservative value of 0.5 rather than 0.2 and add in strawberries and apples as before.

Dr. Unwin has also provided us with an interesting discussion of their use on his Twitter account.

Conclusion

Dr. Unwin has achieved spectacular results for his diabetic patients by reducing or eliminating their dependance on drugs, and in some cases eliminating their disease. All of this has been achieved by reducing their exposure to high-sugar and high-starch processed food.

I have been able to use Dr. Unwin’s tools to reduce my exposure to the same foods. By doing this, I’ve improved my metabolism and increased the odds of stopping the progress of my heart disease.