The short version
- Injected insulin skips the liver, so more of it reaches your fat and muscle than in someone without type 1.
- The carbs you take to treat lows are real calories, and they rarely get tracked.
- Highs and lows during training cost you output, and that adds up over months.
- Log your hypo treatments, judge progress over two to three weeks, and fix the timing and fuelling of your sessions.
One note before the detail. This is how I think about it as a coach who has type 1. It isn't medical advice. Your diabetes team stays in charge of your insulin, so agree any change to doses with them.
I've had type 1 diabetes for most of my life, and I've competed internationally in Olympic weightlifting. Years ago I was training hard without really understanding what insulin was doing in my body, and I ended up in hospital. That's when I had to learn this properly.
1. Injected insulin doesn't work like your own
Insulin is an anabolic hormone. It builds things up, and that includes fat.
Think of your liver as a filter. A working pancreas sends insulin to the liver first, and the liver soaks up some of it before the rest reaches your body.
Injected insulin skips that filter. It goes straight into your bloodstream. So at the same blood sugar level, more insulin reaches your fat and muscle than in someone without type 1. That's a real reason a standard calorie deficit doesn't behave the same way for us.
2. Treating lows adds calories nobody counts
When you feel a hypo coming on, you treat it. Glucose tablets, a banana, whatever's closest. That's always the right call.
But those calories are real, and most of the time they never make it into your tracking app. A couple of treatments a week adds up over a month. It can be enough to take you out of a deficit without you seeing why.
3. Blood sugar swings cost you training
If you're running high, the session feels harder and you don't recover as well. If you're running low, you cut it short or ease off.
It never shows up as one bad day. It shows up as results that come slower than they should.
Put those three together over a month and you get a gap between where your plan should be taking you and where you are. Most people mistake that gap for their own inconsistency.
What to do, starting today
- Log your hypo treatments, even roughly. You don't need to be perfect. You need to see the real number, not a guess.
- Judge progress over two to three weeks. Your blood sugar doesn't move in a straight line, and your weight won't either. That's normal.
- Stop losing sessions to your blood sugar. That isn't a discipline problem. It's a timing and fuelling problem, and that's the part to work on.
- Stop comparing yourself to a generic plan. A plan built for someone without type 1 was never a fair comparison.
Treat insulin like any other limiting factor
An athlete plans around recovery, sleep, travel and old injuries. Insulin is one more thing on that list.
None of this is an excuse, and it isn't a reason to ease off. It's the map you need. Once you treat it that way, your training and your eating both get sharper.