Every recipe in these books has a strip along the bottom with the numbers in it. Here is exactly where they come from, so you can decide how much weight to give them.
They're calculated, not lab-tested
The values are worked out from the weight of each ingredient and published composition data. Nothing in these books has been sent to a laboratory for analysis. That's the honest answer, and anyone who tells you otherwise about a recipe book is being loose with the truth.
What that means in practice
Two zucchini of the same weight can differ in water content. Almond flour varies between brands. How long you bake something changes how much water is left in it. So treat the numbers as a good estimate, not a measurement.
If you need precision — because a doctor asked you to track something — use the numbers as a starting point and check them against whatever tool your doctor told you to use.
Net carbs, and why
The low carb book counts net carbs: total carbohydrate minus fiber. It says so on every page.
Half those recipes lean on psyllium and flaxseed, which are almost entirely fiber. Printing the total carbohydrate figure would give you a number that doesn't describe what you're actually eating. The dessert and air fryer books print total carbohydrate as well, so you have both.
Per serving, and what a serving is
All numbers are per serving, and the serving is stated on the page — one roll, two bars, a quarter of the tray. If you cut it into six instead of four, the numbers change and you'll need to do that arithmetic yourself.
What these numbers are not
They are not a health claim, a medical recommendation or a diet plan. I'm a cook, not a doctor. I can tell you what's in the dish. What you should be eating is a conversation to have with someone who is licensed to have it.