I'm using Carb manager too, but I go by the macros given to me by putting my stats/goals in. My "macros" come out to 24 grams of carbs, 147g fat, 117 g protein, 1900 calories. I'm not dropping weight off quickly, usually 2 to 5 lbs a week, but the macros will be specific to you. Important thing is to try to meet your macros. It's ok to not meet your carbs for the day, but try not to exceed them. Try to meet the fat and protein, but not exceed them, you'll feel more full.
Also if you're diabetic, you need to be careful on Keto, it can cause ketoacidosis.
We did stop last summer on the diet when my wife had her knee replacements, I had lost 42 lbs up to that point, but then got into our same old habits. I gained about 20 back and have lost 4 lbs since last week. i'd probably lose more if I cut my calories down like Don has. In reality I've been consuming about 1500 a day, so still less than my macros. I've been considering doing some intermittent fasting, may try that some next week.