You are picking this up quickly. I'd better start looking over my shoulder!
The '20g' in 20g/day keto-diet is the daily carb amount that would cause most people to enter ketosis state, but some can enter and stay in ketosis for higher carb amounts, for example 30-40g.
The level of ketosis is measured by blood ketone meters or inexpensive urine strips(1). Test strips for blood ketone meters are expensive, at least £1 each, so many are testing once per week or when there is a change. I routinely test on Saturdays at 2pm.
I bought a CareSens Dual blood glucose and ketone monitor 8 weeks ago from
www.spirit-healthcare.co.uk
It is working very well for both ketones and glucose.
Vegetables may not be low carb...
Carb content in grams per 100g vegetable
Low carb:
mushrooms 0.3, celery 0.8, kale 1.4, spinach 1.5
avocado 1.9, celeriac 2.3, leek 2.9, spring-onion 3, squash 3, cauliflower 3, broccoli 3.2,
cabbage 4, okra 4, green/red peppers 4,
turnip 4.7, swede 4.8
Medium carb:
carrots 8, onions 8, peas raw 9, corn frozen 9,
peas mushy canned 11, corn canned 12
High carb:
lentils 13, butter beans 13, kidney beans 13,
baked beans 14, potatoes new 14, black beans 15, chickpeas 16, corn cooked 17, potatoes old 18,
mung beans 19, sweet potatoes 21,
cassava 37g!!!
The really troublesome foods for most people (including myself) with diabetes are: white rice, potatoes (specially potato mash), breads (specially white), pasta, products containing wheat/white flour even small amounts in breadcrumbs and batter for fish and meat. It is useful to take time to measure glucose level after eating (smaller amounts of) these to find out how they affect you.
Example 20g/day keto-diet day (25 Feb 2020):
Breakfast: 6am
50g cheddar 0g carbs,
2 Dulano Mini bockwursts microwaved 2g carbs,
2 poached eggs microwaved 0g carbs
black coffee 0g carbs
Cream Coffe 9am Nescafe + 3 tbsp double cream 0.8g carbs
Lunch: 12noon
2 Angus & Aberdeen Quarter pounders 0g carbs
2 Milbona Processed cheese singles (topping) 2.8g carbs
Cream Coffe 2pm Nescafe + 3 tbsp double cream 0.8g carbs
Dinner: 6pm
5 Kofta meat balls in sauce 10g carbs (2)(2b)
100g celeriac mash 2.3g carbs (3)
50g broccoli 1.6g carbs
blood glucose after 2 hours: 6.7 mmol/L
TOTAL day carbs 20.3g
(1) urine strips work for initially detecting ketosis; not for monitoring extablished ketosis
(2) from recipe I have already calculated and placed in 'myfoods.txt' file for speed and convenience.
(2b) more than twice the carbs I normally eat for dinner 'mains'
(3) carb content of 100g potatoes is 14-18g, white rice is 31g and pasta is 30g. Much too high for a 20g/day keto-diet. Celeriac mash or cauliflower mash are excellent low-carb replacements.