Originally Answered: Low Carb Diet Question?
Those are great questions, and I don't have time to answer them all. Actually you should post multiple questions, you don't have to cram them all into one post.
A lot of people find low-carb works well for them, and there are very fundamental reason for it. There's nothing wrong with ketosis -- no it does not fill your body with toxins (that's silly, it's a natural body process to burn fat). The only problem is that a lot of people find it hard to achieve. For ketosis, yes you have to eat fat. Fat MUST be the majority of your calories. If you eat more than a modest amount of protein, and more than a very few carbs, you won't go into ketosis. Both carbs and protein stimulate the release of insulin, and any insulin will knock you flat out of ketosis.
BUT -- you don't have to be in full-blown ketosis. Eating low carb can still work well even if you don't happen to get as far as the state of ketosis.
Very low carb, moderate protein ... you must get energy from somewhere. Low carb does not mean starving. So yes you must eat fat. There's nothing wrong with eating fat, and it's been a horrible mistake for public health authorities to push the idea that there is (the result of their efforts -- obesity and diabetes at record rates). The idea is based on junk science and politics, it's never been scientifically sound. Americans eat less fat today than 30 years ago, have swapped in more carbs instead, and gotten fatter and fatter.
And in fact you simply cannot live on a diet of lean protein. You can't eat a low-carb, low-fat, high protein diet. It makes people feel bad and no one sticks with it. So please, you need to proudly embrace this: like me, you are on a LOW CARB HIGH FAT DIET. In Sweden, they use the term LCHF, and it's quite popular there.
Ideas for good fat intake: whole eggs, avocado, nuts (best is macadamia nuts), nut butters, butter on everything you want to but butter on, cheeses, FULL-FAT *PLAIN* yogurt, abundant use of such oils as olive oil, macadamia nut oil and avocado oil; olives. And of course meat, the fattier the cuts the better. Chicken legs and bacon are great examples. Good snacks -- deli meat, beef sticks, string cheese, plain yogurt.
Don't worry about putting a bit of onions and carrots in salad. They contain sugar but very little for the amount a person actually uses. You have to eat a significant amount of those vegetables to get many carbs. Unless you're going to sit there and eat two whole onions, it's not enough to worry about.
Don't count calories. The part of this people don't understand is that carbs stimulate an unnatural degree of hunger. Most people don't understand what it is to have NORMAL levels of hunger, which are muted. Eating low-carb, you spontaneously settle into to eating a lower volume of food, and you're satisfied and not obsessive. You can "eat all you want", because you don't want to overeat.
*** Abdul, The only bad fat is transfats (like margarine). Also polyunsaturated seed oils are not great and best avoided. Both are unnatural (seeds are natural but it's unnatural to use an industrial steam press to squeeze useful amounts of oil from them.) If you just stick to natural foods you'll have no problems -- hence animal fat of any kind is good not bad, olive, avocado, coconut oil, butter, sour cream, etc. All of us low-carbers LOVE coconut oil. Fat does not make you fat. I realize it's hard to fully grasp because we've all been brainwashed and misled. If eating very low carbs, you could not make yourself fat by eating fats, even if you were trying to win a bet.
No need to wait to try ketosis if you want to try that. You'll likely lose some weight even if you don't exercise. You won't fatten up. One caution, some people feel week or lethargic right as their bodies convert to fat burning. Don't be alarmed, It's just temporary. If you're eating fat you'll be fine.