The level of carbs to be in ketosis supposedly varies by age, activity, etc except for one older plan by an Austrian doctor, William Lutz, called Life Without Bread. He concluded from years of treating patients, and some studies he did, that in order to lose weight, carbs had to be less than 72g. He allowed more yogurt, fruit than the more common LC induction plan, but could not go over 72g a day or weight loss would not happen. This of course requires some obsessive weighing and measuring, and don’t think I was convinced there was one magic number for everyone, but that was his view (see Plan in green bar above). Working from a restricted food list (no sugar, no starch, no processed seed oils) is easier for me. Even to reduce by 25 g each week will require attention to detail, weighing food, precise measures and carb databases to get it right. If one of the reasons you were not able to maintain the various diets you tried before is that you could not continue managing these details, consider a food list approach.