Obesity is a preventable disease that plagues all the countries of the world, affecting 650 million of its habitants [1,2,3]. In the fight against obesity, a very low-calorie ketogenic (VLCK) diet has consistently been shown to be a useful tool [4,5,6]. Indeed, recent studies from our research group demonstrated that a VLCK diet induces more weight loss than a standard low-calorie diet after 1 and 2 years of follow-up [6]. Among the beneficial effects, the VLCK diet was able to preserve muscle mass, muscle strength [4] and resting metabolic rate [7] and the weight loss was due to fat mass and visceral fat mass [4]. However, obesity is more than an excess body-weight problem [8]. This metabolic disorder is associated with several co-diseases, such as type 2 diabetes, cardiovascular and neurological disorders, and cancer [9,10,11]. Moreover, overweight/obese subjects usually experience a strong desire to eat coupled with a lack of control over eating [12] and suffer from emotional distress and a decrease in quality of life (QoL) and sleep and sexual function [11]. In this regard, few studies have evaluated the effect of weight-loss therapy on the food craving and well-being parameters in overweight/obese subjects.
An interesting effect on sexual function was induced by the nutritional intervention (Table S1; Figure 4). The EMAS-SF questionnaire reported no statistically significant changes for sexual activity in men (Figure 4A). However, the FSFI questionnaire for sexual activity in women evidenced that excitation (p = 0.043) and lubrication (p = 0.013) improved with statistical significance throughout the study. Moreover, from baseline to maximum ketosis, a statistically significant increase was observed in the score for the orgasmic domain (Figure 4B; 0.95; p = 0.034). Based on the FSFI mean total score, women included in this study showed sexual dysfunction (total score = 9.55) at baseline. This total score was improved at maximum of ketosis (total score = 10.48) and at the end of the nutritional intervention (total score = 9.8).
Boosts energy levels. The sluggishness and lethargy you feel after a heavy carb-filled meal is due to the insulin spike and reactive sharp drop in blood sugars. Eating a high-fat diet provides steady energy and helps you avoid crashes that are associated with eating a high-carb diet. Additionally, since ketones are the brain’s preferred source of energy, a ketogenic diet leaves you feeling more alert and mentally energized without having to supply a steady stream of caloric intake [13].
Most low-carb diet authors don't recommend bothering with it. Even many of those who think a ketogenic diet is a good thing just assume that a very-low-carbohydrate diet (under about 50 net grams of carbohydrate) is ketogenic. On the other hand, many people have found that monitoring their ketones, at least for a while, provides valuable information.
Physicians of ancient Greece treated diseases, including epilepsy, by altering their patients' diet. An early treatise in the Hippocratic Corpus, On the Sacred Disease, covers the disease; it dates from c. 400 BC. Its author argued against the prevailing view that epilepsy was supernatural in origin and cure, and proposed that dietary therapy had a rational and physical basis.[Note 3] In the same collection, the author of Epidemics describes the case of a man whose epilepsy is cured as quickly as it had appeared, through complete abstinence of food and drink.[Note 4] The royal physician Erasistratus declared, "One inclining to epilepsy should be made to fast without mercy and be put on short rations."[Note 5] Galen believed an "attenuating diet"[Note 6] might afford a cure in mild cases and be helpful in others.[11]
However, maintaining muscle mass and its functionality (i.e., muscle strength) has an important role in preventing weight regain, maintaining physical functionality, improving cardiometabolic risk factors, and reducing cardiovascular outcomes (5, 7–9, 32, 33). It is commonly assumed, and stated in several textbooks on obesity, that weight loss is associated with an important loss of muscle mass that evolves in parallel with the fat reduction. Some dietary guidelines have even suggested that diets that induce rapid weight loss, such as VLCK diets, create a greater energy deficit and contain lower amounts of protein, and therefore increase the risk of reductions in muscle mass compared with other interventions with more gradual weight loss (34, 35). In this article it was shown that the reductions observed in lean mass were mostly a result of body water loss, both intra- and extracellular. The combined information from the DXA and MF-BIA methods allows for such differentiation (28, 36–38). The loss attributable to muscle mass was minimal (∼1 kg), and an absolute preservation of HG strength was observed, a remarkable fact considering that the patients have experienced a weight reduction of ∼20 kg.
Looking for that hearty crunch that’s packed full of flavor? Look no more. Instead of cracking open a box of Ritz or Cheez-Its, go ahead and make your own! You can make crackers from anything including flaxseed meal (featured in The RULED Book), chia seeds, or even almond flour to make your own homemade crunchy snacks with a delicious flavor of your own.
The keto diet works by eliminating carbohydrates from the your daily intake and keeping the body’s carbohydrate stores almost empty, therefore preventing too much insulin from being released following food consumption and creating normal blood sugar levels. This can help reverse “insulin resistance,” which is the underlying problem contributing to diabetes symptoms. In studies, low-carb diets have shown benefits for improving blood pressure, postprandial glycemia and insulin secretion. (7)
Use fat as a lever.  We’ve been taught to fear fat, but don’t! Both keto and low carb are high fat diets. Fat is our source of energy as well as satiety. The key to understand, though, is that fat is a lever on a low carb or keto diet. Carbs and protein stay constant, and fat is the one you increase or decrease (push the lever up or down) to gain or lose weight, respectively. So if your goal is weight loss, eat enough fat to be satisfied, but there’s no need to “get your fats in” once you’re satisfied.
Food reward regions in the brain programmed much of this physical dependence on processed foods and refined starches. But the body can reverse it. Acute bouts of aerobic exercise have been shown to significantly suppress appetite and hunger while increasing satiety and fullness.6 Exercise in the form of resistance (weight) training can enhance insulin sensitivity,7 which results in reduced insulin secretion.8 Less insulin helps bodies favor fat burning over fat storage.
It’s no secret that carbs—especially refined ones like sugary cereals, white bread and pasta, or sweet drinks—cause your blood sugar to spike and dip. So it makes sense that eating less of them can help keep things nice and even. For healthy people, this can translate to more steady energy, less brain fog, and fewer sugary cravings, Mancinelli explains.
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.
There are vegetables that are high in carbs and others low in carbs. The keto diet recommends sticking to the ones low on carbs but encourages you to eat a lot of them. Best vegetables are all green ones to make it easy. And vegetables that grow above the ground (e.g. lettuce) are always better than the ones that grow below the ground (e.g. potatoes)
Keep up electrolytes. The major electrolytes in our bodies are sodium, potassium and magnesium. Because a low carb diet (especially a keto diet!) reduces the amount of water you store, this can flush out electrolytes and make you feel sick (called “keto flu”). This is temporary, but you can avoid or eliminate it by salting your food liberally, drinking broth (especially bone broth), and eating pickled vegetables. Some people also choose to take supplements for electrolytes, but it’s best to first consult a doctor that understands and supports keto/low carb lifestyles.

Boosts energy levels. The sluggishness and lethargy you feel after a heavy carb-filled meal is due to the insulin spike and reactive sharp drop in blood sugars. Eating a high-fat diet provides steady energy and helps you avoid crashes that are associated with eating a high-carb diet. Additionally, since ketones are the brain’s preferred source of energy, a ketogenic diet leaves you feeling more alert and mentally energized without having to supply a steady stream of caloric intake [13].
^ Jump up to: a b c d e f g Seckold R, Fisher E, de Bock M, King BR, Smart CE (October 2018). "The ups and downs of low-carbohydrate diets in the management of Type 1 diabetes: a review of clinical outcomes". Diabet. Med. (Review). doi:10.1111/dme.13845. PMID 30362180. Low‐carbohydrate diets are of interest for improving glycaemic outcomes in the management of Type 1 diabetes. There is limited evidence to support their routine use in the management of Type 1 diabetes.
This is a wealth of information. My husband and I are starting the keto diet tomorrow and I knew nothing about it. When I sat down to look up information about it, I found this. Thank you! This is everything I need to know in one place. We are not as healthy as we’d like to be and I am optimistic this will help us obtain our goals, along with an exercise plan.
Fats: When it comes to types of fat to consume, anything goes. It’s recommended that you consume a mixture of saturated and monounsaturated fats. Things like coconut oil, which contains medium-chain triglycerides (MCTs) help keep ketone levels high. So long as you’re keeping your carbs in check, if you want to go as far as swigging bacon grease to get your fat in, you won’t be the first.
Here’s a nutritional list of some of the more commonly consumed vegetables on keto. Keep in mind that the weights are the same of everything listed so that it will impact the skew of the carb counts. For example, in a meal you may have 6 oz. of broccoli in the side, but you would not have 6 oz. worth of berries in the morning. You may mix 6 oz. of berries into a pudding with 4 servings.
After 4 months the VLCK diet induced a −20.2 ± 4.5 kg weight loss, at expenses of reductions in fat mass (FM) of −16.5 ± 5.1 kg (DXA), −18.2 ± 5.8 kg (MF-BIA), and −17.7 ± 9.9 kg (ADP). A substantial decrease was also observed in the visceral FM. The mild but marked reduction in fat-free mass occurred at maximum ketosis, primarily as a result of changes in total body water, and was recovered thereafter. No changes in muscle strength were observed. A strong correlation was evidenced between the 3 methods of assessing body composition.
A: The amount of weight you lose is entirely dependent on you. Obviously adding exercise to your regimen will speed up your weight loss. Cutting out things that are common “stall” causes is also a good thing. Artificial sweeteners, dairy, wheat products and by-products (wheat gluten, wheat flours, and anything with an identifiable wheat product in it).
Some negative side effects of a long-term ketogenic diet have been suggested, including increased risk of kidney stones and osteoporosis, and increased blood levels of uric acid (a risk factor for gout). Possible nutrient deficiencies may arise if a variety of recommended foods on the ketogenic diet are not included. It is important to not solely focus on eating high-fat foods, but to include a daily variety of the allowed meats, fish, vegetables, fruits, nuts, and seeds to ensure adequate intakes of fiber, B vitamins, and minerals (iron, magnesium, zinc)—nutrients typically found in foods like whole grains that are restricted from the diet. Because whole food groups are excluded, assistance from a registered dietitian may be beneficial in creating a ketogenic diet that minimizes nutrient deficiencies.
Protein: When people first reduce carbohydrates in their diets, it doesn't seem as though the amount of protein they eat is as important to ketosis as it often becomes later on. For example, people on the Atkins diet often eat fairly large amounts of protein in the early stages and remain in ketosis. However, over time, some (perhaps most) people need to be more careful about the amount of protein they eat as (anecdotally) the bodies of many people seem to "get better" at converting protein into glucose (gluconeogenesis). At that point, each individual needs to experiment to see if too much protein is throwing them out of ketosis and adjust as necessary.
It’s no secret that carbs—especially refined ones like sugary cereals, white bread and pasta, or sweet drinks—cause your blood sugar to spike and dip. So it makes sense that eating less of them can help keep things nice and even. For healthy people, this can translate to more steady energy, less brain fog, and fewer sugary cravings, Mancinelli explains.
To drill down further, there are some genetic enzyme defects that cause problems with ketosis. Here are a few of note: carnitine deficiency (primary), carnitine palmitoyltransferase (CPT) I or II deficiency, carnitine translocase deficiency, beta-oxidation defects—mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (mHMGS) deficiency, medium-chain acyl dehydrogenase deficiency (MCAD).

“A lot of folks find that batch cooking once or twice a week saves a tremendous amount of time and keeps you from spending every evening in the kitchen,” Weaver says. “When keto meal planning, you want to follow general good meal planning practices, like shopping for the week’s food all at once, which helps to save money, and prepping your vegetables when you get home. These 10 keto recipes are so good you’ll forget you’re on a diet.

I’ve been on WFPB diet for 8 months because of high chloresterol and it didn’t drop any, but my husband did the diet with me and his went way down. I have decided to try low carb diet for the next 3 months and do labs to see if it helps. Then I might try keto after that, but between doing WFPB and low carb, I like WFPB best! My doctor said my chloresterol might be “genes”! Loved reading about different diets! I may just need pills or have high chloresterol! Nancy
Conklin's fasting therapy was adopted by neurologists in mainstream practice. In 1916, a Dr McMurray wrote to the New York Medical Journal claiming to have successfully treated epilepsy patients with a fast, followed by a starch- and sugar-free diet, since 1912. In 1921, prominent endocrinologist Henry Rawle Geyelin reported his experiences to the American Medical Association convention. He had seen Conklin's success first-hand and had attempted to reproduce the results in 36 of his own patients. He achieved similar results despite only having studied the patients for a short time. Further studies in the 1920s indicated that seizures generally returned after the fast. Charles P. Howland, the parent of one of Conklin's successful patients and a wealthy New York corporate lawyer, gave his brother John Elias Howland a gift of $5,000 to study "the ketosis of starvation". As professor of paediatrics at Johns Hopkins Hospital, John E. Howland used the money to fund research undertaken by neurologist Stanley Cobb and his assistant William G. Lennox.[10]
Dr. Jockers, thank you so much for this clear and detailed article! I began a keto-style diet around August 2019. By late November, I had fallen from 197 lbs. to under 175 lbs., dropped from 28% to 18% body fat, and anecdotally felt much better in all aspects of my health. All of this occurred exclusively due to diet, I believe– I had almost no exercise routine to speak of, and my desk-based job is pretty sedentary. My family practice doc was surprised and happy with the results as well when I met with him in January… until my blood work came back showing total cholesterol at 257, triglycerides at 236, LDL-C at 162, and HDL at 50.
The goal of a ketogenic diet is to force your body to stop burning its favorite fuel—glucose from the carbs you eat—and start burning fat stores for energy. The body does this by converting the fats to ketones—a state called ketosis. Keto dieters accomplish this digestive feat by cutting way back on their carbohydrate intake. But to do it right, it’s not enough to just guesstimate your carb intake; you could get it wrong and undermine all your efforts. “If you are a beginner to the ketogenic diet, counting carbs is an absolute necessity to avoid frustration in the future,” says Steven Santo, a spokesman for Kegenix/Real Ketones, a keto supplement company. Track your food intake with an app like MyFitnessPal or LoseIt, or just use old-fashioned paper and pen. What you learn may surprise you. “You may be wearing ‘carb-blinders,’ meaning you are unaware of how many carbohydrates you are really consuming in a day,” says Santo. “If you can’t see the number of carbs sneaking into your day, you may be eating many more than you think.”
Previous studies have shown that ketogenic diets preferably reduce the total FM in obese patients (10–13). However, the precise distribution of these losses has not been determined. In this study we confirmed that the diet reduces total FM and specifically visceral adipose tissue, which has a greater impact in predicting cardiometabolic complications associated with obesity than does the total volume of body adiposity (2, 31).
Women were also invited to complete a questionnaire on sexual function (the Female Sexual Function Index—FSFI). The FSFI consists of 19 questions, divided into 6 domains: desire, arousal, lubrication, orgasm, satisfaction, and pain. Each answer is rated on a scale ranging from 0 to 5 or 1 to 5 (0 means no sexual activity in the four preceding weeks) [28]. The total FSFI score, obtained from the sum of the items in each domain multiplied by the domain factor (0.6 for desire, 0.3 for arousal and lubrication, and 0.4 for orgasm, satisfaction, and pain), may range from 2.0 to 36.0. Lower scores indicate poorer sexual function. A total FSFI score less than 26.55 is indicative of sexual dysfunction [28].

I also asked a friend to join me as an accountability partner. She had tried the keto diet before with good success, so having a guide for my myriad questions was a big help. It was also nice to have someone to message at 10 p.m. when I really wanted a cookie so she could commiserate with me. (We agreed the cookie would be delicious, and then ate a cheese stick.)
A CKD on the other hand is a diet where you will eat a minimum amount of carbohydrates per day (that 30-50 gram number) and then on the weekend (or at a time that is appropriate for you) do a large 'carb-up' phase where you will eat a large amount of carbohydrates in an effort to refill your muscle glycogen stores so you can continue to workout the coming week.
I went on low carb diet to lose weight. And it's working - though slowly - at 20 to 30 g of carbs a day. Sometimes a little more. I've been losing about a pound a week. What's really remarkable is I have also reduced my migraines, which were almost nightly. Now the only time I have one is if I happen to drink a beer or glass of wine in the evening. Those I can live without.
Blood specimens were obtained at weeks 0, 8, and 16 after the participant had fasted overnight. The following serum tests were performed in the hospital laboratory using standardized methods: complete blood count, chemistry panel, lipid panel, thyroid-stimulating hormone, and uric acid. A non-fasting specimen was also drawn at weeks 4 and 12 to monitor electrolytes and kidney function.
“I follow and recommend a low-carb or keto lifestyle, with and without intermittent fasting, to all of my patients whether or not they have lifestyle-related chronic conditions. I do this because of the health benefits to anyone who follows them, but also because of the science behind them and the impressive clinical results I have seen in my patients. I have recommended the Diet Doctor website for the past 5-6 years as a first-stop to find completely trustworthy information, delicious recipes, great visuals and excellent videos.”
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