Generally, if someone is planning to do any significant physical activity they normally have a good meal first. This is obviously to build up energy stores in anticipation of using them throughout the activity. We have all done it, be it a day out in the countryside, a days walking or whatever. Athletes obsess about it and there are all sorts of sports nutrition protocols hopefully containing that magic formula to get you over the line first. The last trend I heard of, and I expect I am way behind, was pasta and bananas, with various electrolyte formulas containing glucose in an isotonic mix. The pre- run information pack advised me to take 60-70% of my energy as carbohydrate in the 3 days before the event.
But, not being an athlete, competitive or carb-loading, and certainly not likely to get over the line first, that sort of thing is irrelevant for me.
I have managed to show in previous blogs that a Type 1 can run for around 2 hours without any carbohydrate at all. The last half-marathon a month ago was on almost 100% fat to supply about half of the energy I anticipated I would burn up on the run. I relied on my body to supply it’s own fat to meet the remaining energy balance needed.
So that got me thinking. If I can do half the distance using my body’s own fat reserves, why not the full distance? We are talking only a couple of hours. I need about 1200 calories . Body fat can supply 7000 calories per kg, so 1200 calories is around 170g. Nothing in the grand scheme of things. After all what exactly is a ‘fast’? If we eat say, a couple of hours before a run, does that make the following couple of hours of not eating a ‘fast’? The body will need to get it’s energy from somewhere in that time. ‘It will get that energy from food’, you say. Possibly, and ultimately yes. But it has to be processed first. So, yes, you need energy, of course you do. But it is also true that most of us have enough energy already stored as body fat. I know I have. Even though I am right in the middle of the range of BMI, I have some spare fat. I can see it. Just a hint of a wobble in the mirror. But it is there. And I think too much. If it’s on the outside it is also on the inside. I need to work on that. But that is for another blog at another time. Today is fast day. I have decided just to extend the fast time a bit, from a couple of hours up to 13 hours. I have plenty of on-board energy, no need to eat to take more in. There is no science in this amount of time. 13 hours and 13 miles has a catchy ring to it. Nothing more than that. 13 hours of not eating to allow the ‘tank’ of body fat to empty a bit. It will empty a little because I will still need some energy to burn in order to stay alive whilst not eating! Then I plan to run which will just up the energy expenditure for 2 hours and so will make that fat burn a bit more fiercely. That seems totally logical to me. Everyone I have spoken to thinks this is risky. Mostly because of the diabetes. But diabetes is not a problem if you ignore the carbohydrate. Being a type 1 on a ketogenic diet and then running is about insulin management. Get the insulin right and the body will look after itself. I already know that my basal insulin dose is more than adequate. The challenge here will be injecting exactly the right amount of rapid -acting insulin.
So is there any science here? Well, yes there is! I have not managed to find anything about diabetes and fasting before activity. But there are studies on exercise in fasted non-diabetic athletes trained in LCHF diets. (*). They have found that the body will prioritise metabolism to keep glucose levels in the blood within a constant narrow range. The liver and kidneys will make glucose from scratch if needed. If the demand exceeds supply, all sorts of nutrients are brought in to shore up the situation. Of course fat can be burned to provide energy to tissues that are not glucose dependent. It usually does that anyway. Muscle protein can go to the liver and kidneys and be converted to glucose. Lactic acid produced during physical activity can be converted to glucose ( how good is that?), as can the glycerol part of triglyceride ( the form of fat that is transported in blood plasma). It’s all about getting the right nutrients at the right time. In some of those metabolic pathways, there will be a net energy loss in order to provide the correct nutrient. Making glucose is sometimes expensive in terms of energy, but these metabolic pathways all work out to keep us alive. Insulin is nowhere to be seen. Hormones such as glucagon, cortisol, growth hormone and adrenaline come into play. Of course that is a bit harsh on insulin. It doesn’t just do damage and skulk away. All of those hormones are in a continuous state of balance and tension so when one goes down the other goes up. It is all harmonious. Insulin anyway is just a fall-guy for the wrong foods we put in our mouths. It just does what it does. Insulin does get a bad rap these days, but are we not just shooting the messenger?
Back to the point. What the experiments on the athletes also showed were that, regardless of whether one is eating a low carbohydrate or high carbohydrate diet, the rate of production of glucose, (or gluconeogenesis), does not alter. The amount of glycogen stores did not alter before exercise or after recovery. But the rate of fat burning was higher in the low carbohydrate athletes. And, (And!), muscle will burn fat even if there is an adequate supply of glucose.(*) Well, there you go! Fat burns by preference. So, my body will sort itself out. It will make enough glucose for my needs. Eating is irrelevant for this run. All I have to do is manage the insulin. I am beginning to realise that this way of managing diabetes is not extreme diabetes at all! Exactly the opposite as it happens. The current advice that recommends eating carbs before running with type 1 is the real extreme diabetes! So, I have been preparing for this run thinking that it was I who was taking a risk by fasting. That was reinforced by everyone I knew, medically qualified people included. And now we have a total anticlimax! It will be all of those people with diabetes and who are still carbohydrate counting that are taking all of the risks. I will just be blending into the crowd playing it safe. That’s not how it should have been. But every run so far has taught me that, by following the science of metabolism, I can make decisions on my diabetes that make glucose control predictable and I can be safer by avoiding large glucose swings that are a frequent problem with carbohydrate counting. At least for me it works, and I am sure it will work for others as well. I am curious to see how the fasting works out.
The run itself started in the most bizarre way. My daughter joined me as it was her home-town run. The course was lovely and flat and weaved through a town route, ending with a wide open countryside section at the end. The problem was that the roads were closed from 6 am for a 9 o’clock start. We had planned to meet at her house then cycle the last couple of miles to the starting line. With the roads closed we couldn’t even get to the house. So, the closure of the roads for the run ended up with the runners being unable to get to the start to actually run along the closed roads. Farcical . In the end we had to abandon the car and run 2 miles to the start! We started 20 minutes late. But is was okay as hundreds of people started late. It felt like an organised run rather than a lonely sunday morning slog. It was to be a 15 mile half-marathon today.
Preparation with respect to diabetes was therefore rushed. I had injected the usual reliable 10 units of long- acting insulin before setting out. But in the hour before the run I was so pre-occupied with actually getting to the start that I forgot to manage the rapid- acting insulin. When we arrived at the venue my continuous glucose meter was showing 6mmol/l and a relatively flat trace. The glucose level had not gone up significantly during our 2 mile dash to the start, so possibly wouldn’t. I always expect a bit of a bit of a spike in the mornings and usually shoot up a couple of units of rapid-acting on waking. I had not done that today because of the circumstances. So, what to do with the rapid acting? One unit of insulin reduces glucose by 2.2 mmol/lit. Could I risk dropping any further from 6mmol/l? Possibly the long acting would be cutting in right at the end as well. It usually just keeps the glucose levels flat but can dip throughout the day at a very slow rate. Not a big issue generally but it might be today. In the end I went with 1 unit. That would take the glucose down to just under 4 towards the end of the run. When you are rushing, though, all sorts of untoward things happen. I had decided to take my rapid-acting pen with me just in case the glucose went up. I had an idea it wouldn’t but was unsure. But, having grabbed a pen from my bag to take with me, I had forgotten the needle! So it was a couple of hundred metres run back to the bag drop building. Of course the needle was not in the bag,(it was later found on the floor of the car). But luckily the long-acting pen was there. So I unscrewed the needle from the long-acting pen and used that. Welcome to a day in the life of a person with diabetes.
Once settled in, the run itself was enjoyable. I had good energy levels, and with some one to talk to throughout the miles just reeled away. Glucose levels were okay up to about an hour and a half when it trickled down to 3.5mmol/l at 10 miles. I had a hypo awareness just before the continuous glucose monitor squawked to tell me so. It was no big deal, just an increased sense of exhaustion really. Over the next mile I used 15g of glucose tablets to top up. No drama at all. I opted to walk a couple of hundred metres and use that time to top up with the rest of the fluid. (400ml pre run and 400 en-route). Then off I went. In 10 minutes I felt back to normal despite the squawking of the continuous glucose meter. This is the problem with continuous sensors. They lag a bit by about 20 minutes. But I know it well and like using it. And I felt good so ignored it. At times like this I usually turn it off but as I was in a fasted state I was curious to see what would happen. It took about half an hour for the sensor to register the upswing due to the glucose tablets. But it all was okay to the end of the run. I even managed a small sprint at the end. I felt really good. Type 1 diabetes, 13 hour fast , 15 mile run. Job done! I picked up my medal and kept that. The goody bag I gave away. Grain and honey-based energy bar, Lucozade Sport drink, Banana, Popcorn, and some Good Stuff ‘naturally delicious’ jelly sweets. I had no need of that. In fact I didn’t feel like eating for another couple of hours. So I didn’t.
So, what have I learned? Well, the most important for me is that my rapid-acting insulin is now reliably cutting in at just over an hour and a half. Before I started using a ketogenic diet this was around 3 hours. It has been coming down gradually for several months. It is something to monitor. It might be that I am finally reducing my insulin resistance. Activities like sustained running need a degree of accuracy of management in diabetes so it is wise always to be vigilant. I have also learned that tiny doses of insulin that I now use do not lead to dramatic hypos, just enough symptoms to alert me . I had on this occasion over-injected by just a single unit, but the rescue of that hypo was easy. Also, the science of LCHF in physical activity seems sound. It worked in my case. I have shown that it is possible to fast in Type 1 diabetes and exercise quite safely for a couple of hours.
I have shown over the last 5 half-marathons that what is currently thought of as extreme is in fact the very opposite in reality. Real hard-core extreme diabetes is carbohydrate counting! Fasting before a run is a walk in the park compared to that. I have no doubt about that at all. And, because this blog is about extreme diabetes I will need to join the real crazy gang and carb-load for at least one race. . But at the present time the thought of injecting more than 4 units of rapid acting insulin makes me shudder to think about it. There is still lots to test with the ketogenic diet. I will stick with that. I am not brave enough to take carbs!