It usually takes three to four days for your body to go into ketosis because you have to use up your body's stores of glucose, i.e., sugar first, Keatley says. Any major diet change can give you some, uh, issues, and Keatley says he often sees patients who complain of IBS-like symptoms and feeling wiped out at the beginning of the diet. (The tiredness happens because you have less access to carbs, which give you quick energy, he explains.)
Carol- so sorry to hear about your stroke. I am not sure most doctors would approve of this diet due to most not being taught much on nutrition in med school, and most still believe in the old school high carb low fat way of eating. My experience has been a dramatic drop in my blood pressure in only a few weeks after starting this diet (172/105 down to 144/95!). I suggest giving it a trial of a few months to see how it may work for you.
H. Guldbrand, B. Dizdar, B. Bunjaku, T. Lindström, M. Bachrach-Lindström, M. Fredrikson, C. J. Östgren, F. H. Nystrom, “In Type 2 Diabetes, Randomisation to Advice to Follow a Low-carbohydrate Diet Transiently Improves Glycaemic Control Compared with Advice to Follow a Low-fat Diet Producing a Similar Weight Loss,” Diabetologia (2012) 55: 2118. http://link.springer.com/article/10.1007/s00125-012-2567-4.
A keto diet is very restrictive—more so, even, than plans such as paleo and Atkins. One piece of fruit or a serving of steamed beets can put someone over his or her entire daily carbohydrate limit. “Restrictive dieting is a psychological stressor,” says psychotherapist Shiri Macri, MA, LCMHC, clinical director at Green Mountain at Fox Run, who specializes in working with people who emotionally overeat or binge-eat. “When people deprive their bodies of the amount of nutrition and the nutrients that it needs, the body responds in a state of emergency. Levels of cortisol, a stress hormone, go up, and we also have a decrease in mood-boosting serotonin.” Check out the 11 hidden dangers of the keto diet.
If there's one thing that's for sure right now, it's that the ketogenic diet is insanely popular. People searching for how-to info, detailed meal plans, and high-fat recipes such as keto-friendly smoothie recipes, vegetarian keto recipes, even meals that'll work in the Instant Pot has been steadily increasing throughout 2018. (Related: Is the Keto Diet a Good Idea for Vegetarians?)
Another difference between older and newer studies is that the type of patients treated with the ketogenic diet has changed over time. When first developed and used, the ketogenic diet was not a treatment of last resort; in contrast, the children in modern studies have already tried and failed a number of anticonvulsant drugs, so may be assumed to have more difficult-to-treat epilepsy. Early and modern studies also differ because the treatment protocol has changed. In older protocols, the diet was initiated with a prolonged fast, designed to lose 5–10% body weight, and heavily restricted the calorie intake. Concerns over child health and growth led to a relaxation of the diet's restrictions. Fluid restriction was once a feature of the diet, but this led to increased risk of constipation and kidney stones, and is no longer considered beneficial.
But if no carbs are available, our bodies start burning fat as a primary fuel source and producing ketones in the liver, which the body can turn into energy. This metabolic state, called ketosis, is what happens when someone is starving. But it's also how Harper's body works every day. His system relies on fats like butter, oil, and lard as a primary energy source instead of packing them on as in-case-of-emergency poundage.
I was a Corpsman (not a corpse-man as some recent somewhat fanatical president would say), and I can tell you many stories of Marines and Sailors who maintained restrictive diets (aka picky eaters). Most obvious was lack of sustaining energy (hypoglycemia) at mile 15 (with 80lbs of gear including a 6.5lb rifle and 200 rnds of ammo, etc.) and depletion of essential vitamins, electrolyte imbalance. They were always the first to collapse and have to hear me scold “see I told you so.” An IV of D5W usually does the trick (D is for dextrose, OMG!)
Keto is a very low carb diet, often it means no more than 20 net carbs a day. I had been low carb for 4 years prior to going keto a year ago, my daily carb intake was 50-70 grams a day and the carbs were coming mostly from non starchy vegetables. But yet even being lower carb than the standard American diet, it wasn’t enough for me to still not crave sugar and carbs.
Before starting, ask yourself what is really realistic for you, Mattinson suggests. Then get your doctor’s okay. You may also work with a local registered dietitian nutritionist to limit potential nutrient deficiencies and talk about vitamin supplementation, as you won’t be eating whole grains, dairy, or fruit, and will eliminate many veggies. “A diet that eliminates entire food groups is a red flag to me. This isn’t something to take lightly or dive into headfirst with no medical supervision,” she says.