Zei, Good for you for thinking about this! You may not be out of ketosis with that can of tuna! I am assuming you are testing your urine. The ketone levels change and are hard to follow, especially during the day. I think the best time to test that is first thing, the first pee in the morning. Even then it is not as acurrate as the blood test.

I took this from Dr. Phinney's book.
""Taken from Chapter 13
Ketones-To Measure or Not

As noted in Chapter 1, nutritional ketosis is defined by serum ketones ranging from 0.5 up to 5 mM, depending on the amounts of dietary carbohydrate and protein consumed. In most people, the combined intake of 100 grams of carbohydrate and 100 grams of protein with drive serum well below 0.5 mM. While there is nothing magical about having circulating ketones above this threshold level, it does have the practical value of providing he brain with a virtually limitless, fat-derived fuel source. This alternative fuel is eminently more sustainable, particularly in the insulin resistant or carbohydrate intolerant individual.

Within a few days of starting on our carbohydrate restriction, most people begin excreting ketones in their urine. This occurs before serum have risen to their stable adaptive level….

Meanwhile, the body is undergoing a complex set of adaptations in ketone metabolism. ….

… Over time the urine ketone excretion drops off, ….

These temporal changes in how the kidneys handle ketones make urine testing a rather uncertain if not undependable way of monitoring dietary response/adherence. Testing serum for beta-hydroxybutyrate is much more accurate but requires drawing blood, and it is expensive because it is not a routine tests doctors normally order.""

AND this
""we recommend daily protein intakes between 1.5 and 2.5 gram per day per kg of reference weight. For a person on weight maintaining low carbohydrate diet, this typically translates to somewhere between 15% and 25% of your daily energy coming from protein. ""

So a daily amount at that level for maintaining and lower to lose, along with carb restrictions is what they are reccomending. If you track and are in those levels, I would think you are in nutritional ketosis.

Later,for me, I am going to see how much protein I can eat....