Hi Dave,
I would be really interested to hear how you exercise on so few carbs, I would really like to be more active, but exercise usually equals hypos! and therefore more food, now would be a good time to mention my average daily carb intake on a non exercise day is around the 230 mark (I like my carbs). I eat pretty healthily, I cook all my dinners etc, but I really struggle to find filling low carb or no carb foods and meals, any tips you have would be really appreciated.
Thank you
Finally got some time to put my thoughts down here while sat on a train. Time offline can be useful after all.
As pointed out above, insulin and exercise are not the best of bedfellows (within reason). What you need to understand is what insulin does and what the non-pancreatically deranged body does in response to exercise. Essentially (and yes I'm simplifying here) insulin does three things that are relevant here
1) transport glucose to muscles
2) lay down excess glucose as fat (also prevents/limits its use)
3) suppress glycogen (prevention of liver secretion of stored glucose)
What the normal body does in response to exercise is to significantly reduce the amount of circulating insulin. This is not a problem in terms of glucose transport into cells as you become more insulin sensitive and also there is a Glut-4 receptor which becomes more active and provides a glucose transport function.
That's the potted science bit, and next comes the more empirical/experimental bit with myself as the hamster.
Essentially you need to separate aerobic vs anaerobic exercise as the body responds differently to those, the difference essentially being the release of the stress-based or counter regulatory hormones like adrenaline and cortisol, also glycogen which are in response to stress and serve to provide that liver dump of glucose. In steady-paced aerobic exercise those hormone are absent, or almost so. The difference for me is therefore type of exercise and circumstance. Weights/strength training including yoga for me is always anaerobic; races while having a strong aerobic component as well also have the stress response; interval training is also anaerobic. These can both be characterised as stable or increasing blood sugar.
Aerobic exercise by comparison is where I can find the precipitous fall in BG if I'm not careful. This could be anything from an easy 10k to a 40 mile race (low stress with these).
Here insulin is really not your friend.
You can deal with it in two ways 1) eat more carbs to compensate for the drop, or 2) reduce your insulin dosage or a combination.
Thinking about that, higher carbs diets therefore lead to higher insulin consumption which then lead to higher likelihood of problems during exercise due to residual insulin kicking around.
Things you can do
1) exercise in the morning, fasted, and even before a basal dose if you are MDI - no circulating bolus, limited basal, limited cause for BG to fall.
2) give yourself plenty of time between bolus and exercise. Novorapid is supposed to have a two-hour profile according to my consultant, but that's a load of bollock$ in my experience. Last night for example after a 1U dose for a lunch of left over Indian cauliflower, omelette and a pear, I was at 4.9 at 5:30pm, a 15g carb snack and 5km of running later I was down to 3.9. Another 10g snack and 5km later and I was down to 3.5.
I would therefore give yourself at least 2 hours before exercise, preferably 4+ and be prepared to eat. The only problem there is that this was 25g of carbs that were then preferentially used instead of fat burning.
3) reduce your insulin dose. Both Think Like a Pancreas and Pumping insulin have guides for bolus dose reduction factors, but in my case I have to be more radical than them as I have extreme insulin sensitivity with exercise (been doing it all my life and spent years on training for efficiency).
If you are going to be doing extended exercise then you can also reduce basal. At the extreme end of this for my last 40-mile race I took half a unit of levemir with breakfast of 45g carbs, saw an expected rise to around 12, then a drop back within 3 hours to nearer 7. No more insulin during the race with moderate carb intake over the next 8 hours and was relatively steady at between 5 and 7 most of the time.
So, how to do that endurance stuff on low - moderate carb. Adaptation of diet and training is the key, and it's not an overnight thing. I'd spent about two years prior to diagnosis extending my heart rate based training from cycling to running as well. This allows the creation of a massive aerobic base capable of efficient fuelling and fat burning, so that when you need it you have plenty in reserve at the top end. Reduce your intake of refined carbs. I've had one slice of bread in the entire week so far. Refined carbs are OK as part (but not all) of the fuel used in exercise but add very little nutritional value long term (think burning straw vs charcoal), so try and utilise low GI carbs where you take them. I use things like oats, veggies, fruits, seeds, beans and lentils high fibre stuff. Not too much protein as the excess is turned into glucose by the body. Don't be afraid of fats - monounsaturated fats are a great source of energy and keep you fuller longer, but you need to be aware of the calorie density. Olive oil, rapeseed oil, coconut oil are all good butter and cream are OK as well. Cheese, meat and oily fish are good, but be aware of the protein content as well.
If you really want to you can go ultra low carb, higher fat, moderate protein and try to get into nutritional ketosis (very different from DKA), at which some people have reported significant improvements in overall performance. Some find that as I do, they need to throw in some carbs during exercise, others don’t. For me personally I’d like to have a bash at the ketosis bit, but with my work and travel patterns this becomes quite difficult.
Take today, a quick trip to my office in London, breakfast was a two-egg mushroom omelette, no carbs, no bolus. Lunch will be around 30g carbs with one of the M&S packaged low GI superfood salads and a few handfuls of nuts. Dinner will be no more than 30, maybe 45g carbs.
Other good low carb breakfasts, a cup of coffee and 2-3 handfuls of nuts keeps me full until lunch, or a mix of waitrose frozen berries, sheep or goat yogurt, sprinkled with chopped nuts or flaked coconut for 15g carbs.
Dinners and lunches tend to be the most difficult with my job as it can come down to a sandwich or something with rice, pasta, potatoes etc, but you can simply leave those aside. Dinner for example, my wife makes stir fry, I just have a big bowl of the veg and protein, no rice or noodles.
