The GL of Your Diet Determines Your Future Dementia Risk

The Research Study Findings

The study showed those with a high GL intake – over 110 GL – dementia risk goes up by 13%. Those with a low GL intake – below 49.3 – dementia risk went down 17%.

This study, published in the International Journal of Epidemiology,[1] was based on examining the diet of over 200,000 people in 2011/12 from the UK Biobank data and following up on them more than a decade later to see who had [or had not] been diagnosed with dementia.

Why I’ve Supported a Low GL Diet Since the 1990s

Most people’s diet are over 100 GLs. In the US, 38% of adults over age 20 have metabolic syndrome with high blood glucose levels.[2]

I’ve been advocating between 45 and 60 GLs a day in my low GL diet since the 1990’s to prevent weight gain, fatigue, diabetes and all consequences of metabolic syndrome. To understand exactly what this means – and means to you in relation to what you eat – it’s important to understand what GL is.

GL Explained. How Much Glucose Do You Really Need?

As petrol is for your car glucose is for your body. Glucose is the main fuel of all cells.

(There’s another fuel called ketones, much like cars can also run on electricity. We too are ‘hybrid’.)

Now, here’s an amazing thing. Your body has 100,000 kilometres of blood vessels. Just in your brain there are 1,000 kilometres of blood vessels. Yet, in this entire circulatory system, feeding every one of your 30 trillion cells, each with about 1,000 energy factories called mitochondria, so that’s 30,000,000,000,000,000,000,000 energy factories – there only needs to be 4 grams, or one teaspoonful of glucose[3]. That is literally all you need for every single cell in your brain and body to have energy.

GL is the measure of the amount of glucose in your bloodstream after eating or drinking a food or drink. If there’s not much in your food, and you use it up quickly, perhaps by exercising, blood glucose levels quickly stabilise. The Glyceamic load of a food or drink is calculated from both the quality of the food, and the quantity of carbohydrates (excluding non-burnable fibreFibre is an important part of a balanced diet. There are two type of fibre; soluble and insoluble. Insoluble fibre helps your bowel to pass… carbohydrates) of the food. The quality relates to how fast the glucose in the food releases, which is called the Glycaemic Index (GI). If a food contains lots of fibre and/or proteinProteins are large molecules consisting of chains of amino acids. Proteins are essential nutrients for the human body – they are a building block of…, both of which slow down the release of the sugars in the food, then the GI is less. So the GI or white rice is more than the GI of brown rice, full of fibre. If you ate brown rice with fish, rich in protein, the GI would be less. The GL of that meal depends on how much white or brown rice you ate – a small or big serving. So a small serving of brown rice with fish would be low GL and a large serving of white rice with fish would be a high GL.

What Happens if You Eat More?

So, what happens if you eat more? For example, a can of fizzy, sugared drink like Coke gives 35 grams of sugar – nine times more than the total amount of ‘reserve’ glucose in your bloodstream.

The answer: It is toxic and damages both the blood vessels and the things in it.

A simple example of this is the test used to diagnose diabetes, which is the disease caused by too much sugar in which the kidneys and eyes get damaged by too much sugar. It also damages the brain. “The brain needs the most energy of any organ, so it has the most mitochondria to make it. Sugar damages mitochondria.” says Professor of neuroendocrinology, Dr Robert Lustig, from the University of California, San Francisco.

If you’ve read either my book Upgrade Your Brain or Alzheimer’s: Prevention is the Cure, you’ll know that eating too much sugar, or sugared drinks, or ultra-processed foods (UPF) cranks up dementia risk, worsens memory in young people and is even associated with shrinkage of the same areas of the brain, reducing brain volume, in teenagers.

Are you eating too much hidden sugar?

The simplest way to know if you are on track or off track is to biohack your body’s glucose records. The diagnostic test is called HbA1c. It means sugar-coated or damaged red blood cells. If more than 6.5% (46 or 48 mmol/mol) of your red blood cells are sugar damaged (or glycosylated) this means you have diabetes and if above 6% (42 mmol/mol) that’s pre-diabetes. Even a level above 5.4% (35 mmol/mol) in teenagers predict brain shrinkage. You want to be below 5.4% (31 or 35 mmol/mol). Actually, for really good health you want to be below 5% – certainly below 30 mmol/mol.

It’s such a good indicator of the blood sugar resilience that it’s included in Food for the Brain’s 5-in-1 DRIfT home test kit.

Balance Your Blood Sugar with a Low Glycaemic load (GL)Glycaemic load is a unit of measurement that tells you exactly what a particular food will do to your blood sugar. Foods with a high… Diet – The Rules

Let’s start with something simple.

An orange, for example, will provide a small amount of sugar, a lot of fibre, plus other nutrients. The beneficial fibre puts the brakes on, slowing down the release of that sugar, mainly fructoseFructose is a simple sugar that occurs naturally in fruits, vegetables and their juices, as well as in honey…. which takes time to convert to glucose, and allowing vital gut bacteria to feed on it.

But what if you have a glass of orange juice is the equivalent of three oranges, but without the fibre? Three times the sugar, with no fibre, no brakes on it. So eat your fruit, don’t drink it.

Let’s go one step further. When you eat sugar (glucose+fructose) or rice ( which breaks down to maltose which is glucose+glucose) within a minute you have more glucose in your bloodstream. That’s what digestive enzymesDigestive enzymes break down carbohydrates, fats and proteins into their smallest components, allowing them to be absorbed by the body. Examples of digestive enzymes include… do – break down carbohydrates into glucose. Protein, such as meat, fish or beans, take up to 3 hours to digest and break down in the stomach to ‘amino acids’ which are the building blocks of all proteins, including your cells. This slows down the release of carbohydrates since most carbohydrateCarbohydrates are the primary source of energy for the body as they can be broken down into glucose (sugar) more readily than either protein or… digestion is done ‘after’ the stomach.

Eat Low GL foods, releasing sugar slowly.

So, when you eat rice with beans, fish or meat the sugar in the rice is released very slowly. If you ate brown rice (with the fibre intact) you will release the sugar much more slowly than white rice, and you get more nutrients – it is so much better for you.

Already we have learned three simple rules to balance your blood sugar:

1. Eat fruit. Don’t drink it
2. Always have a sweet or carbohydrate food with a protein rich food.
3. Eat fibre – and make sure it is the primary ingredient in every meal.

If you have three main meals a day of 10GLs and two snacks of 5Gls that adds up to 40GLs a day. So that introduces two more low GL rules:

1. Eat 40 GLs a day to lose weight, 60 GLs a day to maintain it.( In my low GL diet there’s an extra 5 GLs for a drink or dessert.)
2. Eat ‘little and often’ – 3 main meals, two snacks – and start your day with a low GL breakfast.

The balance of your plate

The place to start is the balance of your meals. Since all energy made in the body from burning glucose generates exhaust fumes, it is vital to increase your intake on antioxidantAntioxidants are substances that protect cells within the body from damage caused by free radicals. They help to strengthen the body’s ability to fight infection… rich vegetables and fruit, especially later in life as those energy factories get older and less efficient. It is why half of your plate for meals needs to come from such foods. This is the greens in your main meal or the berries in your breakfast or fresh whole fruit as a snack, eaten with some nuts.

“Balance your plate – half vegetables and fruit, quarter protein, quarter carbohydrate”

Then, as we learn to apply the ‘eat protein with carbohydrate’ rule, a quarter of your plate is either some seafood, meat or bean or lentil or nut. Anything that would grow if you plant it in the ground contains protein. Soya or tofu is a good example.  Such foods needs to make up at least a quarter of what you eat in main meals. These could be two eggs for breakfast, for example.

Eat protein with carbohydrate

That leaves a quarter of your plate for the carbohydrate portion, for example rice, and preferably brown rice, or potatoes or a squash. If you are eating noodles or pasta made from wheat this should be whole-wheat, not the refined white stuff. Your portion, occupying a quarter of the plate, will probably less.

Starchy vegetables and cereals

Technically, that half plate of vegetables, hot, lightly steamed or cold, as in salad, averages 3 GLs. So, with 10 GLs per meal as your goal, the carbohydrate portion of your meal needs to be 7GLs. How much is 7 GLs? This is the main learning – the portion size of the carbohydrate rich food you eat.

Beans and lentils

The best foods for both balancing your blood sugar and giving you the right mix of protein and carbohydrate are beans and lentils.

Controlling Your Blood Sugar

By applying these rules you’ll restore your ability to control your blood sugar balance, regain energy, lose weight if you need to, reverse type-2 diabetes, improve your mental clarity and energy and lessen risk for memory decline and dementias, as heart disease among other health benefits.

Further Information & Support

New Book Out Early 2026 – ‘The 5 Health Essentials’

Extracted from my new book. I provide more details on how to balance your blood sugar and what foods to eat in my new book due out early 2026 – ‘The 5 Health Essentials’.

Read More

Read more about the Low GL Diet on this website or see my books The Low GL Diet Bible, Say No to Diabetes, & The Low GL Diet Cookbook, You may also be interested in understanding how the ketogenic diet works which you’ll find in my books The Hybrid Diet & The 5 Day Diet.

Supporting Supplements

You can find natural support to help balance blood sugar at HOLFORD Nutrition, such as Cinnachrome, GL Support, Carboslow and Get Up & Go with Carboslow.

References

[1] Novau-Ferré N, Mateu-Fabregat J, Papagiannopoulos CK, Chalitsios CV, Panisello L, Markozannes G, Tsilidis KK, Bulló M, Papandreou C. Glycemic index, glycemic load, and risk of dementia: a prospective analysis within the UK Biobank cohort. Int J Epidemiol. 2025 Oct 14;54(6):dyaf182. doi: 10.1093/ije/dyaf182. PMID: 41177554.

[2] Abohashem S, Hassan I, Wasfy JH, Taub PR. Trends and Prevalence of the Metabolic Syndrome Among US Adults. JAMA. 2025 Dec 11:e2521712. doi: 10.1001/jama.2025.21712. Epub ahead of print. PMID: 41379435; PMCID: PMC12699394.

[3] Wasserman DH. Four grams of glucose. Am J Physiol Endocrinol Metab. 2009 Jan;296(1):E11-21. doi: 10.1152/ajpendo.90563.2008. Epub 2008 Oct 7. PMID: 18840763; PMCID: PMC2636990.