Pre-Diabetes – my personal science experiment (wk 1)

In my post I mentioned that I planned to do some research and personally experiment to understand which foods and activities caused a spike in my blood glucose levels.

In week 1 of this experiment, I will be playing around with things, deliberately doing things to skew the numbers a bit, in order to determine what my body does in certain situations.

In week 2, I will be using what I learned in week 1 to try to keep my blood glucose levels stable, and to try work out how to use glucose and glycogen stores effectively to manage both my base levels and my exercise fuelling well.

From what I have determined by reading research so far is that the spike in itself isn’t the main problem at my current levels, but it’s the ability of my body to return levels back to normal that is key. So, if I had a spike after a meal, if my body does it’s job properly, it will provide me with the energy I need and then return my levels back to where they need to be.

The role of insulin

You may, like me, have heard of insulin, but not really have much idea of what it actually does.

Insulin is a hormone whose primary role is to regulate how the body uses and stores glucose and fat. It has an effect of a number of cells in the body, including muscle, red blood cells and fat cells. These cells, with the help of insulin, absorb glucose out of the blood, using it for energy, which in turn lowers high blood glucose levels to the normal range. Follow me so far?

People with Type 2 diabetes find that their body doesn’t react effectively to insulin, and this is termed as insulin resistance. It means the body is less able to get glucose from the blood.

I’m still trying to understand fully insulin sensitivity and resistance, so this will feature in a later blog.

The Experiment

I know that I need to eat less things with sugar in, that’s obvious. But I don’t eat sugar every day, so what else causes blood sugar spikes? This is what I want to know. Recently, even when I’ve been eating pretty well, I’ve been experiencing cravings for something sweet after meals, or in the middle of the day, so I’m assuming that I’m getting highs and lows rather than steady blood sugar levels. I want to understand the factors in my diet that are causing these spikes.

So with a blood glucose monitor in hand, I’ve decided to become my own science experiment.

My monitor measures in mmol/L, (alternative measurement is mg/dL) and the relevant result ranges are shown below

Glucose tolerance test (2 hr Post-prandial)

This is where you fast overnight, take a test, then drink a sugary liquid, then take more tests over 2 hours. The numbers below related to the results after 2 hours. Ideally your levels should drop off within that time

Some sources also detail different expectations for different times of the day, but for my experiment that is something I’ll be mindful of, but I’ll be most mindful of the limits shown above.

My monitor arrived on the evening of 30th September, and so I set myself up a little control, just to see where I currently am, and just how high a normal ‘spike’ is for me. I’m working with assumption that anything below 6.0 mmol/L before meals is good, and below 7.8 mmol/L two hours after a meal is also good. On my results, to help understand the readings, I’ve coloured them green for good, and red for not so good.

Factors that will affect results

I’ve written before that I also have Ulcerative Colitis and although currently in remission, I do get regular checks. One such check is on Monday, and therefore I have to be on a specifically bland (note beige) diet for 3 days before hand. Also, there is a fasting element too & medication. So I figured it could be very interesting to understand what this brief regime does to my blood glucose levels too.

Control – Thu 30 Sept

During the day I had eaten the following (it was what I considered to be a good day)

You might note that I haven’t included any drinks in my food diary. This is because I only drink either water (maybe with a slice of lime in), or weak black tea. Since neither of these has any affect on blood glucose levels, I didn’t see any reason to include them.

Breakfast – 1 wholmeal pitta + 1/2 avocado + scrambled duck eggs

Lunch – Homemade butternut squash & sweet potato soup + 1 slice artisan wholegrain seeded toast, and spread of butter

Snack – Handful of mixed nuts and corn.

Del was cooking dinner, but it was quite late in the day, and I was starving by the time I took my first test

Dinner – Vegetable Pilaf, made with white rice.

After dinner my sweet tooth returned, and as Del had bought some Turkish Delight we shared that. I thought it would also be a good test on how quickly sugary foods would clear my system.

I took my 2nd test just before bed.


118:52Before Dinner5.2 mmol/L
222:39Before Bed10.2 mmol/L

Day 1 – Fri 1 Oct

My decision was to decide what I would have for breakfast once I knew my fasted test result on waking up. It was somewhat higher than I was expecting (I guess Turkish Delight stays a while in your system), and so a very healthy porridge option was my choice

Breakfast – Whole porridge oats, with KoKo milk, flaked almonds, seeds and a handful of frozen berries. Nothing to sweeten it just cinnamon

Lunch – Baked sweet potato fries, baked beetroot, quorn sausages with onions & salad (no dressing)

Dinner – I had 2 ‘fake’ kebabs and salad. These kebabs are a (processed) vegan alternative to kebab meat that is low in calories, reasonable in protein and full of kebab goodness taste, without the drippy fat. They are a wonderful ‘dirty food’ pleasure but without the guilt.

I also had carrot stick & hummus and a handful of mixed raw nuts.


108:29Fasted before breakfast7.2 mmol/L
210:091 hr after breakfast10.3 mmol/L
311:55Before lunch4.4 mmol/L
421:50Before bed7.8 mmol/L

Day 2 – Sat 2 Oct

1st day of pre-op bland low residue diet – urgh!

Absolutely zero of the healthy food I would normally eat is on the menu today. See the picture to show the restrictions.

Since I was going to be eating a high carb day, I decided to test out something else that I have recently discovered about insulin sensitivity- which is what we need for our blood glucose to act as it should.

During exercise your body burns glycogen, which is a form of glucose stored in the muscles. After exercise muscles replenish their glycogen stores with glucose from the bloodstream. Therefore, the more glycogen is burned during activity, the longer the body’s insulin sensitive is improved. The more intense and longer duration activities can improve insulin sensitive for up to two days

I got very excited about this finding, and so the results of today’s tests, in particular in the afternoon have been very interesting. I have eaten a lot of carbs, and consumed quite a chunk of sugary snacks, and yet my blood sugars although high, are not as excessive as I would have expected. It will be interesting to see if they are still elevated tomorrow morning.

Breakfast – bacon white bread sandwich (pescatarian credentials slip when food choice is limited)

Lunch – white bagel with scrambled egg and cheese.

5 fruit pastilles

Dinner – macaroni cheese. It’s one of my favourites so takes my mind off the beige nature of today’s food options.

Evening snack – bar white chocolate (after all those white carbs, the craving for something sweet was strong)

Exercise – I hour on the turbo trainer, fuelled by a whole pack of fruit pastilles.

108:29Fasted6.7 mmol/L
214:321 hr after lunch7.3 mmol/L
318:06After exercise & sugary sweets9.3 mmol/L
423:07Before bed10.2 mmol/L

Day 3 – Sun 3 Oct

More blandness and then the fast begins – oh, and I forgot to mention the additional drugs.

After overloading on fruit pastilles, chocolate and white carbs yesterday I was expecting my numbers to remain high this morning, but, hey presto, my morning reading was the lowest so far. RESULT! Does this mean that as long as I do an hours worth of decent exercise each day, it will neutralise the effects of my indulgences? Probably not, but it’s certainly worth exploring.

I’m already finding on this experiment is that all of my preconceived notions on how the body reacts to sugar are being turned on their head. The general advice if you have pre-diabetes is to reduce sugar, improve your diet, lose weight and get more exercise. But if you largely follow this regime anyway, there isn’t really any helpful advice out there on what the most effective way to tweak things. By doing this experiment it’s allowing me to tweet things as I go so that hopefully I’ll find the right formula for my daily fuelling requirements

All my food today will be consumed before 2pm, as my medical fast starts after that, with only clear liquids allowed. Today’s exercise will be strength and weight training, fuelled only by breakfast rather than sugar. I am very curious as to whether ultimately there will be a crash later in the day, especially since my food sources will be limited.

It is interesting that after exercise, & with only breakfast some hours earlier, my levels rose a bit. Then several hours later, and with only a carb based lunch inside me, they were slightly higher at bedtime. I’m not really sure quite what to make of these findings. I had expected levels to crash if I’m honest.

Breakfast – (early) white bagel. (Later) scrambled egg on white toast with bacon.

Lunch – Remainder of Macaroni Cheese

Dinner – Plain Miso Soup


108:17Fasted4.8 mmol/L
213:21After exercise but before lunch6.5 mmol/L
323:55Fasted since lunchtime other than fluids7.8 mmol/L

Day 4 – Mon 3 Oct

Fasting all morning, then the hospital, then I get to eat normally again

The day of my procedure. No food until around 4pm, but also sedative given in afternoon. Not the best of days.

Breakfast – None

Lunch – None, although Cheese & pickle sandwich and some biscuits after my procedure

Dinner – Fish, Chips and mushy peas…..well I was starving


19:24Fasted4.8 mmol/L
213:17Fasted, pre op (taken in hospital)4.2 mmol/L
315:38Fasted, post op (taken in hospital)4.0 mmol/L
418:262 hrs post sandwich & biscuits7.8 mmol/L
522:25Before Bed7.1 mmol/L

Day 5 – Tue 4 Oct

Sadly my hospital visit has highlighted the return of my Ulcerative Colitis, so now I have yet another reason to be looking closely at my diet. It looks like I will need to start paying even more attention to eating an anti-inflammatory diet. Then I should be able to tackle both issues at once.

The experiment continues.

My rather indulgent fish & chips last night didn’t have a particularly lingering effect on my blood glucose levels this morning, which was good. Although wouldn’t have been particularly helpful in in my UC symptoms battle, but that’s not really the subject of this experiment.

I’m back on the bike for a couple of hours later so will try again to fuel my ride with sugar based snacks, and directly after my evening meal to see what the impact is, and to set a control scenario to compare next weeks ride to.

Breakfast – Overnight oats with chia seeds, protein powder mixed seeds, cinnamon and frozen berries. Made with Koko milk.

Snack – white bagel with peanut butter

Lunch – skipped

Dinner – Wholemeal mushroom pasta bake

Ride Snacks – 2 x mini racer bars (Aldi version of Snickers).


108:09Fasted6.2 mmol/L
212:07Before snack4.9 mmol/L
322:53After exercise5.7 mmol/L

Day 6 – Wed 5 Oct

I shall be going for a short run later this evening, so again, let’s see how exercise impacts the results

Breakfast – White Bagel, Cream cheese, smokey bacon

Lunch – Carrots, cucumber, tomatoes, sweet potato pakora, hummous, apple


Dinner – Missed before run, chinese takeaway after run (I wonder how that will affect my glucose)


107:57Fasted5.1 mmol/L
220:44After run (before food)5.4 mmol/L
322:24After Food5.5 mmol/L

Day 7 – Thu 6 Oct

An average day is planned today. I planned to do a turbo session this evening, but we went out to dinner instead. Such is life, plans change quickly.

Breakfast – White bagel and peanut butter

Lunch – Carrots, cucumber, tomatoes, sweet potato pakora, hummous, home made nachos & halloumi

Dinner – Went out for dinner, seafood pasta, & calamari starter


108:44Fasted6.1 mmol/L
215:44After Lunch6.0 mmol/L
322:25After Dinner6.3 mmol/L

Thoughts on the first week

There was quite a lot to take in from the first week of my experiment. It’s clear however that if I was to continue to have the kind of random diet that I have had over this week, then I am likely to remain firmly in the pre-diabetic range. My numbers were rarely below 5.5 mmol/ in the mornings, but weren’t always in the higher range during the day.

I can’t quite work out why my numbers were very high (up around 7-10 mmol/L towards the beginning of the week, but didn’t go so high again after my hospital procedure, despite some rather sugary attempts to bring the numbers up. It’s possible that something in the pre-procedure prep had the effect of resetting my glucose sensitivity for a short time. Maybe if there’s a doctor reading this, you can advise.

Also, towards the middle of this weeks experiment, there was more exercise, and so it’s likely that had a stabilising effect.

It didn’t seem to matter too much what I ate after exercise, as it didn’t push my glucose levels to really high levels, which is great news. I hope it wasn’t an anomaly. Of course, for my other condition (Ulcerative Colitis) I should take some care with what I put in my body.

What was very interesting was that at no point did I have a glucose crash. On Wed I went out for a run and cycle, at moderate intensity, and hadn’t eaten anything except an oatmeal cookie since lunch, and yet when I checked my levels after they were pretty stable, and even after the late Chinese meal that had (as I was feeling a bit lazy), it didn’t really spike. Although in the morning my levels were a bit higher than normal.

For week 2 of the experiment I shall be trying to eat ‘properly’ and am starting to look at upping the anti-inflammatory aspects of my diet (due to the discovery of a return to my colitis), and also lowering my fasting glucose levels. I hope to find a balance that also keeps my numbers stable over the week, but also fuels my exercise, which will be increasing over the next few weeks.

But first, there’s a small matter of a weekend away in London to deal with. What could possibly go wrong…..?

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