Strategies for exercising without having to eat

What are people doing so that they do not have to eat prior to or after exercising? I am trying to lose weight but most of the time am having to eat extra food either before starting or after finishing to avoid lows. I feel as if I’m just replacing the calories I’m burning. I have tried reducing insulin (either basal or bolus) before or during exercise but when I do this it’s virtually impossible to get it right, and I end up going low or, more often, going high, which isn’t good either. I am trying to lose weight, which is why I would rather not have to eat every time I exercise if I can avoid it.

Any tips on the best way to handle shorter cardio workouts (usually 45-60 minutes) without having to eat, and/or the best time to try and cut back insulin to avoid highs? I try cutting back bolus insulin if I’m exercising within about three hours of eating, and use a temporary basal rate if it’s longer, but as I said a lot of times it’s overkill and I end up with high blood sugar either before exercising or after.

Also, does anyone have any handy form that can be used to record the effects of exercise (i.e., BG before, length and intensity of exercise, BG after, any insulin on board or carbs eaten)? If I recorded such information maybe it would be easier to guage how much I will drop from a given type and duration of exercise.

Common for T1s to go high after intense exercise. Afternoon is the least problematic time for my BG, but the least convenient time to do it.

I don't have a pump to adjust basal, so afraid I'm no help there. I don't eat meals hours before exercise & eat a small amount of protein before. I have a protein powder shake with very few carbs. Easy to digest. Protein seems to work to keep things level (well, more level) for me. Figuring out how to handle a real work-out is a royal pain. I've opted for long walks (hilly where I am) & weights instead.

For peak performance blood sugar should be between 125 and 200, with 150 being the best to shoot for. If you DON"T eat your body will burn fat and muscle in large quantities to fuel itself producing ketones. DKA sucks. I advise against it.

Think of working out NOT as burning your calories, but as building muscle. The more muscle you build the more calories you burn. One pound of muscle burns about 30 calories per day just existing. But if you don't fuel the muscle properly it won't be able to grow and work better.

Anaerobic workouts (heavy weights, sprinting, etc.) utilize fast twitch muscle fibers which excite the fight or flight response. Simply put, your body pumps out adrenaline. Adrenaline causes the liver to release glucose stores to get your sugars up (thus giving you more energy to hit that 150 mg/dl mark). This is why weight lifting and sprinting cause an immediate rise in sugars (in most people) followed by a delayed drop.

Aerobic activities (running, cardio, light and fast weights) do not have this surge of adrenaline. Thus your body will burn the sugars in your blood lowering your BS over time. The lower you go the less energy you have. The less energy you have the worse your workout will be.

On the handy form, just buy a memo pad. In mine I start with wake up BS, WHAT I ate for breakfast WITH the carb count (you'll find working out certain carbs hit at the best time. My preference is cheerios), injections etc. One hour after breakfast I go to the gym, note the time and BS. I jot down what I did (nothing fancy, just chest x4 meaning four types of chest exercises). I know what it means so shorthand is fine. I test every half hour I work out. I don't treat highs in the gym or until one hour minimum after finishing (if I'm artificially high from working out the combination of insulin and the end of workout low can make a person hypo hard). Then I test when I leave and an hour afterwards UNLESS I feel off, in which case I test, test, test.

Also, I don't eat any different on workout days than non-workout days (other than a protien shake after I finish working out - protiens build muscle so it's very important). I simply bolus less. If my breakfast would ordinarily require 4u Novalog I would take 1 or 1.5u. You have to figure this out on your own. Easiest way is to be consistant (at least at the start). Eat the same thing at the same time and go to the gym at the same time. You don't need to do the same thing at the gym but you do need the same exertion each day. Look at your BS numbers. Did you eat too little or bolus too much and go low? Bolus less or eat more (so long as you have the carb energy in the food bolus less). Perhaps you ate too early or late, and your food peak arrived before or after your gym time (try to get them to line up together - like I said me, cheerios, one hour and I'm at the gym). Writing this down in a little pad takes maybe five extra minutes a day. It doesn't have to be neat. I doubt anyone can understand mine.

Cardio is done to improve the performance of the heart (think of it as weights for your heart). Try some aerobic style weightlifting. Basically it's light weight fast reps. That makes your muscles toned, not big and Arnold like. My personal favorite is walking around the gym at a decent clip either doing bicep curls with 10lb weights (to give you an idea of % of weight my heavy weight for curls is 60lbs) or throwing a medicine ball in the air and catching it, alternating side to side (still walking). Look into classes (many community centers have them at lower costs than the gyms), a few sessions with a trainer (2-3 just to learn the techniques) or befriend someone knowledgable. Don't be afraid to ask questions and DON"T be embarrased or put off if someone is in better shape than you. They were in your shoes at one point in time and are more than happy to help/provide encouragement.

One last bit of advice - talk to your doctor and find a "Panic" number on the high end for when you workout. Mine is 275. So long as I'm below that I keep going and treat later. On the flip side I won't go below 100 at the gym. I have a fear of a bar crashing down on me if I pass out mid-rep. Basically so long as I'm in that range I wait until at least an hour after and then treat conservitavely. If I usually would take a correction dose of 4u I would take 1 or 2. My sugars might still be coming down on their own.

Hope this long winded rant helps, sorry for the spelling, and if you'd like any advice feel free to talk to me. 6 years in the AF brainwashed me into liking the gym :D

Using ketones for energy is not the same as DKA. The goal of losing weight is to burn fat.

Low ketones, a natural process of using fat for energy, is nothing to be concerned with. It's not harmful or risky. Almost everyone (diabetic or not) would show mild ketones in the morning simply from fasting overnight. This is the purpose of fat storage--energy reserves.

Ketosis is different from diabetic ketoacidosis (DKA). With DKA, the body is in starvation mode because a lack of insulin prevents glucose from getting into cells, thus intense hunger no matter how much food is eaten. Since cells aren't able to utilize glucose that's circulating (starvation) fat is burned to pump out more glucose, but this doesn't help. BG gets dangerously high, electrolytes are imbalanced (acidic blood) & dehydration occurs. More complex than this, but that's the short version.

I am like Gerri and find that afternoons work better as far as BS goes. Energy wise, I like evenings better but that is always the hardest time to figure out BS. If I know that I am going to exercise & need a snack first, I always count those calories in my daily total that I planned to eat and not in addition to what I was going to eat – that way, I am still sticking to how many calories I wanted to eat. I haven’t figured out how to get the temp basals and exercising working for me either – like you, I end up going high after.

I don’t know if this will help any, but Gary Scheiner had an article on DiaTribe with some multipliers to adjust insulin by when you are exercising.

I agree with Gerri that afternoons are the best time to exercise, from a BG perspective, although I also agree it's not always convenient? I check my insulin on board with my pump and if I am having a big workout day (to me, an hour is big?), I will arrange my eating to have some time before. I think that if you do that, 10G of carbs, like skim milk or V8 or other veggie juice, are good for fuel, there's a little spike but it seems to be to be 'softer' than 'food' or 'sugar'? Maybe it's some sort of glycemic index issue. I keep meaning to read a book about that but have not quite gotten to it just yet?

I take Gatorade too but mix like 3 scoops into a bottle and let the running mix it up, that way I have 45G of carbs if there's an 'emergency' but will just take maybe 1/4 of the bottle at a time every 3-5 miles when I'm running. Ideally, I'll be 90 when I start, turn my pump down to about 60% basal rate and watch the pre-run snack run me up to 120 after the first couple of miles, then start to go down slowly a mile or two after that and have the 10G 'hits' of carbs as I continue?

True, however if you continuously exercise without carbs in your system to fuel your muscles your body breaks down the fat, releasing ketones. No matter how much insulin is in your system if there isn't glucose present from carbs your body will break down the fat and release ketones. Not a big deal usually. Keep doing it day after day (as in you don't want to eat carbs because you are defeating the purpose of working out) and it will compound and eventually become DKA. Opting out of eating carbs is no safer than going off your insulin to force your body to burn fat.

Also, ketones are not used for energy, they are a byproduct. "Fat, on the other hand, is a 'dirty' source of energy. When fat is burned, there are waste products produced. These waste products are called 'ketones'. Ketones are acid molecules that can pollute the bloodstream in large quantities." (Think Like a Pancreas, Scheiner, Pg 187)

"Ketone production can also be induced by a lack of carbohydrates in the diet. During periods of starvation, prolonged fasting, or restricted carbohydrate intake, the body's cells must resort to burning alternative sources of fuel: namely fat and protein [muscle]. With increased fat metabolism and limited carbohydrate metabolism, ketone production may exceed the body's ability to eliminate them." (Think Like a Pancreas, Scheiner, Pg 189)

"Ketones are the chemical by-products of fat breakdown, just as ashes are the by-product of burned wood." (The Johns Hopkins Guide to Diabetes, Saudek/Rubin/Shump Pg 289)

"What causes ketoacidosis?

Here are three basic reasons for moderate or large amounts of ketones:

  • Not enough insulin
    Maybe you did not inject enough insulin. Or your body could need more insulin than usual because of illness.
  • Not enough food
    When you're sick, you often don't feel like eating, sometimes resulting in high ketone levels. High levels may also occur when you miss a meal.
  • Insulin reaction (low blood glucose)
    If testing shows high ketone levels in the morning, you may have had an insulin reaction while asleep." (ADA website, Near end of page)

If we burned ketones as energy they would disappear, burned up by our muscles.

Keytones, as you state, are the byproduct of the metabolism of fatty acids. The body in turn can use the ketones for energy. The brain, heart and muscles can all burn keytones. Excess ketones can be eliminated through urine and via breathing. The body needs to do this because the ketones are acidic. All this is a normal process and is not dangerous. Ketone levels remain low.

Ketoacidosis or DKA is the result of out of control blood sugar and out of control ketones. The ketones overwhelm the bodies ability to either burn them or eliminate them and the blood becomes acidic . This condition is life threatening.

Hi Jennifer,

One thing I've been trying is exercising about forty-five minutes to an hour after a meal (usually breakfast or lunch) for which I've either not bolused or cut back radically on the bolus. In this way, the carbs I consume aren't extra; they're mealtime carbs that I'd probably be consuming anyway. I thought it would be uncomfortable exercising so soon after eating, but it's actually working out okay. Depending on the length and intensity of the exercise session, I may also reduce my basal. There's still quite a bit of trial and error involved, but, like you, I was getting frustrated by having to eat so much extra stuff, thus defeating the calorie-burning aspect of the exercise. (That said, I like Suftromi's notion, above, of thinking about exercise as strength-building rather than calorie burning.)


Thanks for explaining this further to Jennifer because your previous post made it sound as if she exercised without eating carbs she was risking go into DKA.

Something that's not mentioned in the sections quoted is that about 58% of protein eaten is converted to glucose, so it's not just carbs that fuel our bodies. I've been eating low carb for over 2.5 years (30-35 carbs daily). No lack of energy for exercising or running around non-stop every day.

Exactly. While ketosis and DKA are different ketosis can quickly lead to DKA if the ketones are unmonitored and unchecked. Seeing as how DKA can set in within hours and has a mortality rate (as far as I can tell, numbers are all over for this) of between 1 and 5% at least why risk it? Yeah you can lose weight but---you could very well die as a result.

So the point is why drive yourself into ketosis by not consuming carbs before a workout? Especially doing it day after day which will drive ketone levels up and up.

And why does spell check not know the word ketones on a diabetic website? Seems like it's a good word to know....

Ketosis & DKA are very different animals. Mild ketones/ketosis doesn't turn into DKA. While ketones are present from restricted carbs & ketones are present during DKA, the causes are from an entirely different set of circumstances, which I explained above. I think you're confusing the issues. I'm probably in ketosis most of the time from low carb eating. Persistently high ketones accompanied by persistently high BG is a different situation & is a perscription for DKA. DKA is not going to be induced by exercise from not eating carbs before exercising. The whole goal of losing weight is to burn fat reserves & this isn't courting death.

There's isn't a spellcheck on Tu D. Are you using Firefox? Firefox has spellcheck.

As others have stated, it's not really the calories that you burn while you exercise that are going to make the difference when it comes to weight loss.

As for eating prior to or immediately after exercise, if you can figure out a way to avoid spiking your BG before, feel free to share. I adjust my basal for any cardio that's going to last longer than 30 minutes but, for the most part, I have to shoot for a BG between 120-140 before exercise or I won't get through my typical 30 minute cardio routine.

Eating after exercise is pretty much a necessity because, to some extent, you have to replace lost glycogen stores, provide amino acids to rebuild/repair muscles, or both. The literature is mixed about the best time post-exercise to eat, so you have to figure out what works best for your own BG control and exercise goals.

Personally, the best time for me to exercise is an hour or so after breakfast. I generally get nice stable BGs throughout the day and through the night if I can exercise in the morning. If I exercise in the afternoon, I'll run into BG issues after dinner. Evening workouts are fine, but I'll have to watch my overnight BG pretty carefully.

Hey Heather,

Same here.

Huh, first time Firefox has failed me. At least it's not Internet Explorer - the #1 web browser for obtaining a new web browser....

Anyway, ketosis can lead to DKA (as my endo explained it anyway) under certain circumstances. Basically what she said is that the increased ketone levels under ketosis (starvation ketosis) are fine. Unless you lower your insulin levels and increase glucose levels. If you go hard on weights (I do) then you do both these things to get your best performance; the anaerobic activity as we all agree jacks your sugars up first then down. The liver releases sugar due to the adrenal response of the anaerobic activity which is the cause for the raise. I intentionally (approved by my endo) have a reduced insulin level to allow my BG to climb where I want it. Now we're getting into ketone production. If I already put my body into ketosis then I have X amount of ketones in my system. The workout places Y amount of ketones in my system. My body can only process Z amount of ketones. If X+Y>Z ketones will rise, and if left unchecked (no days off etc) will build and make the blood acidic. If I remember my chemistry class the body runs a PH of 7.35. Ketosis lowers this to about 7.25 to 7.3. Mild DKA begins at about 7.2 and sever DKA occurs at around 7.1. That is not a large margin for error. As I said, this is what the Endo told me.

Point being ketosis doesn't equal DKA. But combine with a few other things and there is a risk. Will it happen? Probably not. But with a mortality (fancy word for death) rate of 5%, I'm not running that line without due caution.

Besides, I like my cheerios too much to go down to 30g/Carbs a day :)

Firefox doesn't know carbs either. I need to fix the spell check.

My spellcheck doesn't recognize carbs either. No, I don't mean crabs:)

There really isn't a risk. Having mild ketones, which are flushed away & remedied by drinking water, does not increase chance of DKA. Ketones are not poison. Mild ketones, the kind produced during weight loss, does not lower blood pH. Mild ketones are effectively removed through respiration (CO2), drinking water & through the buffering actions of minerals in the blood. Not something you have to worry about during exercise.

When electrolytes are severely imbalanced through the complex biochemistry of DKA, then there are problems. DKA is a condition of insufficient insulin resulting in high BG & cells being starved for glucose because of lack of insulin to get glucose into cells. The body is in starvation mode, protein & fat are depleted in an attempt to stave off starvation. Dehydration no matter how much liquid is consumed. Starvation no matter how much food is consumed. High ketones are a DKA symptom, not the cause.

Ah, the way they explained it to me is ketones can effectively build up to cause the PH imbalance creating DKA. So the 7.35 goes to 7.3 through ketosis and then the additional build up further drives it down. Would that change with kidney damage?

Really!?!? Firefox knows ketosis but not ketones?

Lol, crabs....

Not sure if this going to show up in the right place. When there are replies to replies to replies, after a while they show up any place in the discussion.

Yea, I eat crabs & keytones--lol! Better than having crabs.

With respect to your doc, but that's not how it works. Our bodies efficiently deal with mild ketones without them building up. I'm probably in ketosis continually from eating 30-35 carbs daily. Test for ketones first thing in the morning with first urine of the day before eating or drinking anything. Most people will show mild ketones simply from not eating overnight. Drink a large glass of water & test again. Don't know if kidney damage changes the ketone equation. It probably would depending on how severe the damage is.

Well, I guess I have weighed in before that I believe that you lose weight through changes in your diet and that I don't really think that cardio is very good for weight loss, but we all need to make our own choices. In your case, you wish to do cardio.

Here is my suggestion for exercising without eating: Mixed cardio and aerobics. Either intervals ( or what I would term split sessions. Do 10-15 minutes of cardio, with 10 minutes of weight training. Hard weight training, not with those pink dumbells. Inserting weight training cycles will hopefully cause a blood sugar rise through a cascade of hormones (adrenaline and cortisol). That may well be able sustain you for additional 10-15 minute cycles of aerobics avoiding the need to treat a low. As an alternative to weight training you can do sprints, I'm not talking 4 mph jogs, but running as fast as you can till your lungs burn and your wegs feew wike wubber.

I do so agree Gerri. When I am fasting during the Advent season ( not a total fast) and very low-carbing, I am always in mild ketosis, with very normal blood sugars. Several years ago, I had to explain this to a nurse at an urgent care, where I went after an ankle twist,. She had never seen a diabetic pass mild ketones in the urine with a finger-stick blood glucose of 95. She thought I was a physiological oddity until I explained ketosis to her.

THANKS, suffroml, for your deatiled info on how you exercise and chart. it will help me with my New year's Resolution to exercise more and more carefully.

God Bless,