That first drop might be mostly water weight. But research suggests that the keto diet is good for fat loss, too. An Italian study of nearly 20,000 obese adults found that participants who ate keto lost around 12 pounds in 25 days. However, there aren’t many studies looking at whether the pounds will stay off long-term, researchers note. Most people find it tough to stick with such a strict eating plan, and if you veer off your diet, the pounds can easily pile back on.
Very low calorie diets are designed to bring on a mild form of ketosis, which means your body shifts from using primarily carbohydrates to fat as an energy source. The relative safety of ketosis is a hotly debated topic. In very low calorie diets, which are medically supervised diets, ketosis is supported for a short period of time to produce rapid weight loss in people who are extremely obese. It's not something you try at home simply because you want to lose a few pounds. Very low calorie diets and ketosis in people who are simply overweight can be dangerous.
As a gut health doctor, this is my biggest pet peeve about keto diets: They sometimes overemphasize foods high in dietary fat like meat and full-fat dairy at the expense of gut-supporting plant foods. Knock your gut flora out of balance and you're almost sure to hit a plateau since gut health affects weight loss. Even on the strictest keto diet, you can incorporate fermented and cultured foods including sauerkraut, kimchi, and kefir.
A ketogenic diet helps control blood sugar levels. It is excellent for managing type 2 diabetes, sometimes even leading to complete reversal of the disease. This has been proven in studies. It makes perfect sense since keto lowers blood-sugar levels, reduces the need of medications and reduces the potentially negative impact of high insulin levels.
Similar to our results, three studies noted that diabetes medications were reduced in some participants[6,8,9], although details were provided in only one study. We also discontinued diuretic medications during diet initiation because of concern for additional diuresis incurred by the diet. This concern was based on the theoretical effects of the diet [17], observed effects of the diet on body water by bioelectric impedance [18], and practical experience with the diet [19]. Until we learn more about using low carbohydrate diets, medical monitoring for hypoglycemia, dehydration, and electrolyte abnormalities is imperative in patients taking diabetes or diuretic medications.
An important strength of this study was the use of 3 different techniques for determining body composition in different settings, i.e., obesity and no ketosis, marked reduction in body weight with high ketosis, and finally, substantial reduction in body weight without ketosis. The tight control of adherence by daily measurement of B-OHB is another relevant strength of this work. A potential limitation of our study could be the sample size; however, because each subject underwent 4 evaluations, enabling each individual subject’s own results to be compared, this adds statistical power to the study and a real difference between the experimental points.
If you think about it, one of the diets that follow these principles is the low-carb ketogenic diet. It focuses on highly-satiating foods like meat and low-carb vegetables while cutting out all processed, carb-ridden, and highly-palatable foods. By eating in this way, most people experience tremendous amounts of fat loss — not because insulin levels dropped or the body got a metabolic advantage from burning fat, but because keto dieters tend to eat significantly fewer calories than before without realizing it.
In the 1960s, medium-chain triglycerides (MCTs) were found to produce more ketone bodies per unit of energy than normal dietary fats (which are mostly long-chain triglycerides).[15] MCTs are more efficiently absorbed and are rapidly transported to the liver via the hepatic portal system rather than the lymphatic system.[16] The severe carbohydrate restrictions of the classic ketogenic diet made it difficult for parents to produce palatable meals that their children would tolerate. In 1971, Peter Huttenlocher devised a ketogenic diet where about 60% of the calories came from the MCT oil, and this allowed more protein and up to three times as much carbohydrate as the classic ketogenic diet. The oil was mixed with at least twice its volume of skimmed milk, chilled, and sipped during the meal or incorporated into food. He tested it on 12 children and adolescents with intractable seizures. Most children improved in both seizure control and alertness, results that were similar to the classic ketogenic diet. Gastrointestinal upset was a problem, which led one patient to abandon the diet, but meals were easier to prepare and better accepted by the children.[15] The MCT diet replaced the classic ketogenic diet in many hospitals, though some devised diets that were a combination of the two.[10]
“Our medical practice was featured implementing a low-carbohydrate plan for a patient with type 2 diabetes in the documentary The Magic Pill. We believe food can be used as medicine. Many of our patients with insulin resistance, diabetes, metabolic syndrome, PCOS and more will see excellent results and resolution of chronic disease states with low-carbohydrate diets. Education and understanding as to which dietary strategy is best for the individual is essential in reclaiming one’s health. There is no doubt in my mind that low-carbohydrate planning can be extremely useful and safe for the appropriate clinical scenario.”
The key to hitting my number was to plan, plan, plan. I worked out all three meals, down to the condiments, plus snacks on the weekends. If I knew what I was having and what I was "allowed" to have while staying under my carb goal, I found managing the infrequent cravings and hunger pangs easier. I can't stress enough the importance of planning for a keto diet.
As of 2016 it was unclear whether low-carbohydrate dieting had any beneficial effect on cardiovascular health, though such diets can cause high LDL cholesterol levels, which carry a risk of atherosclerosis in the long term.[9] Potential favorable changes in triglyceride and HDL cholesterol values should be weighed against potential unfavorable changes in LDL and total cholesterol values.[31]
In regard to serum measurements, the mean fasting glucose decreased by 17% from 9.08 ± 4.09 mmol/L at baseline to 7.57 ± 2.63 mmol/L at week 16 (p = 0.04) (Table ​(Table4).4). Serum sodium and chloride levels increased significantly, but only by 1% and 3%, respectively. Uric acid level decreased by 10% (p = 0.01). Serum triglyceride decreased 42% from 2.69 ± 2.87 mmol/L to 1.57 ± 1.38 mmol/L (p = 0.001). Increases occurred in both high-density lipoprotein (HDL) cholesterol (8%) and low-density lipoprotein (LDL) cholesterol (10%) but these changes were of borderline statistical significance (p = 0.08 and p = 0.1, respectively). The following blood tests did not change significantly: total cholesterol, potassium, bicarbonate, urea nitrogen, creatinine, calcium, thyroid-stimulating hormone, and hemoglobin.
Although studies have shown that the keto diet can reduce seizures for children with epilepsy, there is no evidence indicating that keto helps with other brain disorders or improves mental cognition, according to Harvard Health Publishing. Some studies show that keto may lower blood sugar for people with type 2 diabetes, but there is not enough long-term research to determine whether it’s safe and effective for diabetics.

For those looking for something just a little closer to real sugar, you can use Xylitol. It cooks and tastes very similar to sugar, but it has a slight glycemic impact (13 vs. 100 for sugar). It is great, but please keep in mind that it is very toxic to animals and it will raise insulin levels slightly. These are the two most cited reasons for not using Xylitol.
While it may be new to you, the keto diet has actually been around since the 1920’s, when the Mayo Clinic reported its effectiveness for helping epilepsy (that is still the case). Since then, there’s strong evidence that the keto diet helps with weight loss as well as type 2 diabetes, prediabetes, and metabolic syndrome, says Jeff Volek, Ph.D., RD, professor in the department of Human Sciences at The Ohio State University in Columbus, Ohio and co-author of The Art and Science of Low Carbohydrate Living.
In most circles, ketosis refers to nutritional ketosis, an optimized state in which you burn fat instead of sugar. Nutritional ketosis has been used to treat epilepsy since the 1920’s and its popularity for mental acuity and weight loss has surged recently. More technically, ketosis refers to a metabolic state in which most of your body’s energy comes from ketones in the blood, as opposed to glycolysis, in which energy supply comes from blood glucose. Ketones are the energy source made by the body (in the liver) when there’s not enough carbohydrates to be burned for energy demand, so the body turns to fat for energy. The body enters ketosis when blood sugar levels are below a certain level, and liver glycogen is no longer available to produce glucose for energy.
Prolonged ketosis and large buildups of ketones can be dangerous, but VLCDs intentionally bring on mild ketosis. At a certain level, ketosis brings on desirable changes that facilitate safe weight loss and keep important body processes working properly while getting so few calories. When your body is using fat for energy, you may be losing weight, but your brain can be starving because it primarily uses glucose, or carbohydrates, for energy. However, ketones can cross the blood-brain barrier and supply most of your brain's energy needs, according to Wim Saris, a researcher writing in the November 2001 "Obesity Research" journal. Without ketones fulfilling this role, your body will begin to break down amino acids, your protein building blocks, into blood sugar. This can cause you to lose lean muscle mass while on the VLCD.

It’s also currently as trendy to the fitness world as kale and açaí are to the pseudo-hipsters who wear beanies, even in the dead-heat of summer. If you haven’t tried keto on for size, maybe give it a go (unless you’re a complete and utter carb bitch, and cramming yourself full of bagels and pancakes just makes your abs really pop - in which case, the rest of us hate you on the inside. Just a little.)