Assuming that you’re interested in getting started on this way of eating, I guess the most appropriate next step would be providing information as to just how to actually get started.
As I stated in the first post (which I hope you read but if not ((you really should – don’t be lazy!)) I’ll reiterate here) your brain needs about 100g of carbs a day to maintain its functioning. That means that any diet under 100g of carbs will necessitate the production of glucose via gluconeogenesis, where protein and fat can be turned into necessary glucose. This basically means that it’s possible to survive at basically no incoming carbohydrate, but it would be difficult, not to mention depriving you of other necessary nutrients from plants and/or dairy.
That said, ketosis will kick in once you’ve depleted your glycogen stores and not eaten carbohydrate within a varying amount of time. The process of depleting all body glycogen, which is stored in muscles and in the liver, can take 24 to 48 hours, generally, depending on your last meal, amount of muscle mass, and level of physical activity. Anecdotally, I’ve never taken longer than about two days to start ketosis, and the very first time I went on a ketogenic diet, I was very sedentary and weighed about 450 pounds, so extra glycogen depletion through physical activity was basically non-existent.
The best way to get into ketosis quickly (and with a fair degree of certainty) is to wake up and do a day where 5% or less of your calories come from carbs. The gold standard for “induction” or the process of entering ketosis is about 20-25 carbs or less, and these should come from high-fat dairy sources and vegetables. If you’re getting all 20 carbs in one sitting from a plate of candy or a slice of cake, it will hamper or even prevent ketosis, as that will flood your bloodstream with glycogen and trigger an insulin response. The true underlying hormonal mechanism for the production of ketones is the ratio of insulin to glucagon, but unless you’re exceedingly interested in that chemical relationship, I will pass on explaining it here, as it’s not really important. Just know that if your insulin is up, and you’re non-diabetic, then your production of ketones (and the breakdown of fat for energy) will be hampered.
With a day of restricted carb intake, with some added high-intensity aerobic training (ask your doctor before starting any exercise routine, particularly if you’ve never really worked out before) or weight lifting, you will likely enter ketosis by the following day or night, again, depending on mitigating factors.
Once in ketosis, it is highly recommended that you get daily exercise. Well, actually, you should always get daily exercise, but with ketosis, even just some good-paced walking on a daily basis will help improve insulin sensitivity, burn more fat, and improve overall fitness. This is especially important during the first month or so – you’ll definitely want to increase exercise, particularly if you’re like I was and severely overweight – but that first month of transition will make strenuous exercise difficult, and you’ll burn out easily.
What to eat in order to enter and stay in ketosis? Well, that’s a pretty broad range of foods. The easiest thing would be to say to not eat any sugar, grains, flour, etc. and focus entirely on nuts, eggs, low-carb dairy, meat, fish, and vegetables, but there’s really more to it than that. To really be restrictive about your carbs, and especially if you’re paying attention to nutrition facts, you’ll see that a lot of things have 1 or 2 grams here and there and that will really stack up. Lunch meat is a huge one, because you might think that it’s just meat, should be fine, but the curing process most deli meat undergoes uses sugar of some sort at some point, and that adds carbs, not to mention meats preserved with nitrates or nitrites are intensely unhealthy and should be avoided 99% of the time unless there’s really no other option.
Probably the easiest way to look at it would be:
Whole, un-cured meats, even fatty cuts (don’t be afraid of fat!)
Fibrous, green veggies, but also tomatoes and onions, in reasonable amount. My opinion on more carby vegetables like tomatoes and onions (I know tomatoes are a fruit, so before you get uppity, did you know they’re a nightshade?) is that the benefits outweigh the increased carbs. Besides, you’re unlikely to eat a whole onion at once anyway.
High fat, low carb dairy, like heavy cream, cream cheese, and cheddar. No low fat nonsense. They replace the healthy, naturally occurring fat with sugar and other crud.
Eggs, eggs, eggs. Their benefits are nearly impossible to exaggerate, but they’re probably going to be a staple for your diet.
Seafood – wild caught or nothing. Farmed seafood is fed a bounty of disgusting crap, including quite literally crap. From corn and wheat to chicken poop, farmed seafood, particularly tilapia and salmon, is very, very unhealthy for people and the environment.
Certain nuts. Almonds, walnuts, pistachios, macadamia nuts – these are all good. Peanuts and peanut butter are good, only if you get all natural and are very strict with what you eat. 2 tablespoons of natural (just peanuts and salt – Smuckers is the best I’ve had, anecdotally) is about 4 carbs, so again, be cautious. Cashews unfortunately are very carby, and should be avoided.
Starchy veggies like potatoes, yams, corn.
Cured meats – sausage, salami, pepperoni, etc. Nearly all deli meats, too. The good news is you can find meats like these that aren’t cured. I buy bacon at Aldi that is thick cut and free of nitrates and nitrites, and it’s amazing.
Low fat anything. Milk, cheese, etc. Mainly an issue with dairy foods.
Highly processed “low carb” food replacers. You’ll see a lot of bars and snacks marketed to low carb dieters, but very few are worth trying. Quest brand snacks are, in my experience, really, really great. They taste good, are high in fiber, and the products they’re made from are real food instead of chemicals.
There’s acceptable levels of fruits, mostly berries, once you’re in ketosis and have stabilized your blood sugar. Again, if it fits into your macros, you can try it, but I’ll write more on that later.