I want to start out by sharing a link that explains a common misconception about ketosis and keto-acidosis:
Ketosis or keto-adaptation is not dangerous but very helpful. Ketones are what our brain and our muscles use for fuel when there is no glucose. Only when our carb intake goes under about 50 grams/day does our body start fueling significantly with ketones that are made from fat. This is the reason why people on low-carb (under 50 grams of carbs) diets can lose weight quickly and without hunger. Their body has learned that fuel comes from fat, either body fat or fat in the diet because there are not enough carbs to burn. The human body does need some glucose but it can manufacture the necessary glucose through gluco-neogenesis in the liver. Since gluconeogenesis will only happen when the glucose is needed this will not lead to excessively high sugar levels in the blood as happens when we eat high-carb foods which will then cause a rise in insulin. Insulin will lower the blood sugar level quickly, but the result is that the low blood sugar level will make us hungry for more carbs. By eating a low-carb diet, our body gets in the habit of burning ketones for fuel and blood sugar levels are much more stable. This is why people on ketogenic (very low-carb) diets can easily skip breakfast, exercise without fueling or even do some intermittent fasting without feeling hungry.
When people on ketogenic diets increase their carbs a little, to the level where they are still relatively low-carb, but not ketogenic, these benefits often go away.
This is what happened to me several times when I fell back into old habits of eating. The most recent one was using supplements that contained sugar when I felt sick, another was eating more fruit because we had it for free in your garden. At other times I really wanted to enjoy a piece of chocolate but low-carb chocolate is still hard to find and somewhat time-consuming to make, so the regular stuff put my carb levels over the limit. The level at which a person switches from primarily burning ketones to primarily burning sugar for energy varies a little bit. Some people will stay in ketosis with almost as much as 100 grams of carbs/day while others need to stay at 20 or 30 grams/day.
This is why the popular Atkins diet recommends starting at 20 grams of carbs/day for 2 weeks and then increasing gradually from there.
The only disadvantage could be that reducing the amount of carbs to 20 grams would eliminate not only fruit, but also dairy and some vegetables and these things have nutrients we may not want to miss. For this reason Dr. Atkins recommended that people take a supplement during the very low-carb induction phase of his diet.
At 50 grams of carbs/day I have a much wider choice of foods that fit in my eating plan. The only thing I eliminate completely are grains and beans and sugars, none of which I really miss. Nutrient-wise my diet is complete, allowing for all the essential nutrients in my diet on a daily basis. I have every intention to stay on this level of carbs for life because it is tasty and easy to maintain.
I want to finish with the words of two of the leading researchers in low-carb nutrition, Jeff Volek and Stephen Phinney, who have this to say in their book: "The Art and Science of Low Carbohydrate Living":
This process of keto-adaptation is a powerful metabolic state because it means your cells have a sustained fuel supply thanks to a steady release of energy from body fat. (p. 39)