Another option is to decrease the intake of carbohydrates slowly, over a few weeks, to minimize side effects. But the “Nike way” (Just Do It) may be the best choice for most people. Removing most sugar and starch often results in several pounds lost on the scale within a few days. This may be mostly fluids, but it can still be great for motivation.
Low carb, high fat diets have been used for centuries by doctors when working with obese patients. William Banting published the widely popular booklet titled ‘Letter on Corpulence Addressed to the Public’ in 1863. In this booklet he explained how he had slimmed down by eating a diet high in fat void of carbs. The Banting diet was used for decades by individuals looking to lose weight.

Test blood ketones in the late morning or afternoon. Blood and urine ketones vary throughout the day, as well as from person to person. Many people find that their blood ketone levels are usually lowest right after waking up. Try testing later on, preferably a few hours after eating. Even if you’re only in ketosis for a portion of the day, you’re still getting some benefits, as discussed in this talk by Dr. Steve Phinney: Achieving and maintaining nutritional ketosis.
Over 3 mmol/l is higher than necessary. It will probably achieve neither better nor worse results than being at the 1.5–3 level. Higher numbers can also sometimes mean that you’re not getting enough food (“starvation ketosis”). In people with type 1 diabetes, ketone levels over 3.0 mmol/L can be caused by a severe lack of insulin that requires urgent medical attention.