How many carb grams raise you, say, 10 mg/dl?
You have a tester. Do some research on yourself.
Do not eat for 4 hours. What is your mg/dl?
Take half a glucose tablet, 2 grams. Chew it and let it melt in your mouth. Test in 3/4 hour. What is your mg/dl?
How’s your math? If 2 grams raise you 10 mg/dl. You can figure that 10 grams will raise you 50 and you can figure what your snack will raise you by looking at the box’s nutritional values for carbohydrate grams and the amount you took.
Now do research on what 1 unit of insulin lowers you. Once again find a time 4 hours after you’ve eaten and test: ____ mg/dl.
Take 15 grams carbohydrate. You can figure how far up that’s going to put you: maybe 60 mg/dl? _______
One hour later see where you are. Are you above 140?
If yes, you can give yourself 1 unit of short acting insulin and test 3 hours later for its full effect. Where did it put you? ______
So now you know what 1 unit of insulin will drop you.
Now you can answer your questions yourself, based on what happens to you.
I must caution you that the 30 units of Lantus you take may wear out at 18 hours so that no research should be done 18 hours after you’ve taken Lantus. Likewise, Lantus gives a peak to some people at 6-8 hours after the dose.
The only way you will know what Lantus does is to keep from eating one meal a day, and test to see that you’re staying in your target zone during that part of the day after you miss your meal. An appropriate dose of Lantus will not drop you below 80 nor let you rise above 120.
I imagine the doctor/dietitian is hoping that Novolog for the snack will tide you over the period Lantus may not work as well.
Many of us have learned to divide the Lantus into two doses, one at 7 am which takes us to bedtime, and a much smaller dose at bedtime for our cells’ needs at night. This means that we do not take a snack and Novolog at bedtime. Giving the snack and Novolog is simply an alternate way of attaining the same thing: in the target zone all night. Sometimes it happens and sometimes not.
I want to caution you that if you are going down below 70 during the day, your Lantus dose is too high, and needs adjusting downward. That adjustment downward in Lantus can be by 2 units. Do not change it more often than every 3 days. Your body will not stay the same. You need to keep close dated and timed records of what you ingest in carb grams and what you take in units of insulin. Use a tiny notebook.
Do spend the time researching yourself. Do not take a set amount of Novolog if your “meal” changes in the amount of carb grams you’re taking.
Learn how much carb grams you’re taking, how far up it will take you and how far down a unit of insulin will take you. Then you will be able to set a “carb ratio”. You will say to yourself, I use a ratio of 1 unit insulin for every 10 grams carb I take.
Congratulations on asking the kinds of questions that are needed. Do tell us further what units your Novolog “shot” is, and what grams of carb you find you’re eating each meal! You will get the hang of it.
I don’t know where you can find Walsh’s book online for free, but a lot of Bernstein is on line.