“The mission of Diet Doctor says it all: Make low carb and keto simple. For over a decade the website has been an invaluable resource for evidence-based nutritional advice and support for anyone seeking to lose weight and improve health with diet. And the results speak for themselves. By building a nutritional safe harbor, available to anyone, anywhere, anytime, Dr. Eenfeldt and the Diet Doctor team have revolutionized the delivery of nutritional information for the greater good of a world that needs it desperately.”
A final guideline: Even if you’re keto, portions of fat still matter, says Jill Keene, RDN, in White Plains, New York. “How much you specifically eat depends on your calorie needs and goals, but overconsuming fat can cause weight gain,” she says. Also, considering fat is your body’s main fuel source on a keto diet, she advises spreading out your fats evenly throughout the day.
“As an American board-certified endocrinologist who moved back to Mumbai, I saw India’s diabetes epidemic and dogma through a different lens. Low carb plus intermittent fasting has proven very effective in the reversal of insulin resistance, fatty liver, PCOS, reduced fertility, obesity, metabolic syndrome, hypertension and even early diabetic neuropathy and nephropathy. I conduct Diabetes Self-Management classes every month while looking at the whole lifestyle: stress, sleep, exercise, mindfulness, self-care and nutrition. This works even in India’s predominantly vegetarian culture! I often refer patients to DietDoctor for low-carb recipes and FAQ’s.”

“[This study] does support other existing research findings that you can indeed lose weight on a ketogenic-inducing diet, and higher levels of protein intake, while following a calorie-restricted diet does help preserve the loss of lean muscle mass,” says Lona Sandon, PhD, RDN, assistant professor in the department of clinical nutrition at the University of Texas Southwestern Medical Center in Dallas.
You know you’re in ketosis by checking blood ketones with a hand-held ketone meter (a test for beta-hydroxybutyrate). A ketone meter can be purchased online for about $100-120, along with ketone test strips. You prick your finger and use a drop or two of blood to measure ketones. Aim for 0.5-3.0 mm. I use Precision Xtra, which can check for both ketones and glucose in the blood (useful if you’re overweight). Some people measure ketones in the urine or via a breath taste, but I’ve found them to be not as accurate.
Variations on the Johns Hopkins protocol are common. The initiation can be performed using outpatient clinics rather than requiring a stay in hospital. Often, no initial fast is used (fasting increases the risk of acidosis, hypoglycaemia, and weight loss). Rather than increasing meal sizes over the three-day initiation, some institutions maintain meal size, but alter the ketogenic ratio from 2:1 to 4:1.[9]
The ketogenic or “keto” diet is a low-carbohydrate, fat-rich eating plan that has been used for centuries to treat specific medical conditions. In the 19th century, the ketogenic diet was commonly used to help control diabetes. In 1920 it was introduced as an effective treatment for epilepsy in children in whom medication was ineffective. The ketogenic diet has also been tested and used in closely monitored settings for cancer, diabetes, polycystic ovary syndrome, and Alzheimer’s disease.

“I recommend low-carbohydrate, high-fat (ketogenic) diets to almost all my patients to improve their quality of life. The LCHF diet reduces inflammation, promotes weight loss, and improves blood biomarkers without prescription agents. The result is improved sleep, sharper mental clarity, more energy throughout the day, and healthier relationships to food. Most patients suffer “fat phobia” but fat does not make you fat! Sugar does! We teach patients to eat lots of healthy fats and cycle in and out of ketosis. We refer everyone to Diet Doctor as a great resource, especially for the carb contents of various food and drinks.”
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.
“In my psychiatric practice, the high rate of obesity and metabolic disorders among my patients prompted me to develop an integrative therapeutic response, especially to address frequent patterns of impulsivity/compulsivity, low energy/lethargy, mood instability, mental fog, poor concentration and cognitive deterioration. A real-food, low-carb, healthy-fat, often ketogenic lifestyle, combined with intermittent fasting, stress management, rest, and movement — and appropriate pharmacotherapy as needed — results in improved general health, cognitive function, mood management, and quality of life. Diet Doctor, especially the new Spanish site, is a great tool for my patients.”
There are numerous benefits that come with being on keto: from weight loss and increased energy levels to therapeutic medical applications. Most anyone can safely benefit from eating a low-carb, high-fat diet. Below, you’ll find a short list of the benefits you can receive from a ketogenic diet. For a more comprehensive list, you can also read our in-depth article here >
Another concern for obese individuals is physical activity and sexual functioning. Relevantly, an increase in physical activity was observed during the intervention. This improvement agrees with the design of the nutritional intervention because the commercial weight-loss program (PNK method) includes lifestyle and behavioral modification support. All patients underwent a structured program of physical exercise with external supervision. According to these results, patients are encouraged to walk and to practice vigorous exercise.
Keto flu is a real thing. Cutting your carbs to the bone and going into a state of ketosis (where your body burns fat for energy) can bring on a cluster of uncomfortable symptoms, such as headaches, fatigue, muscle aches, nausea, and diarrhea. The side effects are the result of your body transitioning to using fat as its primary source of energy instead of carbs, explains Kristen Mancinelli, MS, RDN, author of The Ketogenic Diet. Once it adapts to the new fuel source (usually within a week or two), you’ll start to feel better.
Available research on the ketogenic diet for weight loss is still limited. Most of the studies so far have had a small number of participants, were short-term (12 weeks or less), and did not include control groups. A ketogenic diet has been shown to provide short-term benefits in some people including weight loss and improvements in total cholesterol, blood sugar, and blood pressure. However, these effects after one year when compared with the effects of conventional weight loss diets are not significantly different. [10]

First, I want to thank you for all of your dedication and work in providing this site. The difficulty of maintaining a healthy weight is a big problem for so many people. My personal question & issue in staying on Keto is my craving for fresh fruit. This a.m I had a large fresh peach along with my “Bullet Proof” coffee. Have I now sabotaged today’s Keto eating?
“I prescribe ketogenic whole-foods diets because they are powerful metabolic interventions with the potential to address root causes of psychiatric disorders, including inflammation, oxidation, and insulin resistance. I enthusiastically recommend the Diet Doctor website to all my patients because it is the most comprehensive resource for low-carb news, advice, science, inspiration and support in the world. The information there is trustworthy, easy to understand, available in multiple formats and languages, and funded entirely by the people.”
Providing additional support Paoli et al. (17) examined the effect of a modified KD diet (~55% fat, 41% protein, and 4.5% CHO) on performance and body composition in gymnasts. In a crossover design, researchers compared independent 30-day dietary regimens consisting of “normal diet” (WD; 46.8% CHO, 38.5% fat, and 14.7% protein) and modified KD in nine elite male gymnasts. There were no significant changes from pre to post during either dietary intervention for measures of physical performance, indicating the absence of significant dietary CHO did not negatively impact physical ability. The post-KD measurements, however, saw a significant decrease in fat mass (pre: 5.3; post:
Low-carbohydrate diet advocates including Gary Taubes and David Ludwig have proposed a "carbohydrate-insulin hypothesis" in which carbohydrate is said to be uniquely fattening because it raises insulin levels and so causes fat to accumulate unduly.[8][28] The hypothesis appears to run counter to known human biology whereby there is no good evidence of any such association between the actions of insulin and fat accumulation and obesity.[6] The hypothesis predicted that low-carbohydrate dieting would offer a "metabolic advantage" of increased energy expenditure equivalent to 400-600 kcal/day, in accord with the promise of the Atkin's diet: a "high calorie way to stay thin forever".[8]
A slice of cheese contains 115 calories, 7 g of protein, 9 g of fat (5 g of saturated fat), about ½ g of carbohydrate, and no fiber, per the USDA. The saturated fat qualifies it as a food you ought to limit, but some research suggests the food has health benefits as well. A meta-analysis published in December 2017 in the European Journal of Nutrition found that cheese eating was associated with a 10 percent lower risk of heart disease and stroke, particularly for those consuming about 1.5 oz (or a slice and a half) per day.
Much of the research into low-carbohydrate dieting has been of poor quality and studies which reported large effects have garnered disproportionate attention in comparison to those which are methodologically sound.[5] Higher quality studies tend to find no meaningful difference in outcome between low-fat and low-carbohydrate dieting.[5] Low-quality meta-analyses have tended to report favourably on the effect of low-carbohydrate diets: a systematic review found that 9 out of 10 meta-analyses with positive conclusions were affected by publication bias.[5]
Carbohydrate has been wrongly accused of being a uniquely "fattening" macronutrient, misleading many dieters into compromising the nutritiousness of their diet by eliminating carbohydrate-rich food.[26] Low-carbohydrate diet proponents emphasize research saying that low-carbohydrate diets can initially cause slightly greater weight loss than a balanced diet, but any such advantage does not persist.[26][6] In the long-term successful weight maintenance is determined by calorie intake, and not by macronutrient ratios.[7][6]
There are so many tricks, shortcuts, and gimmicks out there on achieving optimal ketosis – I’d suggest you don’t bother with any of that. Optimal ketosis can be accomplished through dietary nutrition alone (aka just eating food). You shouldn’t need a magic pill to do it. Just stay strict, remain vigilant, and be focused on recording what you eat (to make sure your carb and protein intake are correct).

Weight loss is a common target for disease management, as well as health promotion. The prevalence of obesity remains high among U.S. adults (36.5%) (5), as well as children and adolescents (17%) (6). Importantly, obesity is a significant contributor to increased morbidity and mortality, as well as being a primary driver of increasing medical expenses (4). Despite much effort and cost, there has been little success on this front and obesity remains a public health crisis.


WY conceived, designed, and coordinated the study; participated in data collection; performed statistical analysis; and drafted the manuscript. MF assisted with study design, performed data collection, and helped to draft the manuscript. AC analyzed the food records. MV assisted with study/intervention design and safety monitoring. EW participated in the conception and design of the study, and assisted with the statistical analysis. All authors read and approved the final manuscript.
The popular belief that high-fat diets cause obesity and several other diseases such as coronary heart disease, diabetes, and cancer has not been observed in recent epidemiological studies. Studies carried out in animals that were fed high-fat diets did not show a specific causal relationship between dietary fat and obesity. On the contrary, very-low-carbohydrate and high-fat diets such as the ketogenic diet have shown to beneficial to weight loss.
In a 2004 study, overweight and obese adults consumed a low-fat diet and a low-carb diet for one week each. Both diets were designed to reduce each person’s calorie intake by 500 calories per day. However, people lost more weight and body fat after the low-carb week than the low-fat week – even though the men averaged higher calorie intake during the low-carb phase.
Polycystic ovary syndrome (PCOS) is the most common endocrine disorder, and it affects women of reproductive age. Symptoms include obesity, hyperinsulinemia and insulin resistance. A pilot study took 11 women through 24 weeks of a low-carbohydrate ketogenic diet (20 grams or less per day). Among the five who completed the study, they lost 12 percent of their weight on average and reduced fasting insulin by 54 percent. Additionally, two women who previously experienced infertility problems became pregnant. (6)
“I have been recommending low-carb and ketogenic diets to my family practice and consultation patients since early 2017. Diet Doctor is an incredibly valuable resource for my patients; counseling low-carb would be much more difficult without all the great information available. My orthopaedic pre-habilitation, diabetes, mood disorder, Alzheimer’s, PCOS, cancer, and obese patients all benefit from low-carb. Low-carb has brought back the joy in family medicine!”
Still, there are limitations to the keto diet. The first few weeks on the diet can be rough, and cause what’s known as the keto flu. And some people may experience side effects like thyroid or hormone imbalance, adrenal fatigue, poor sleep quality, and extremely dry eyes. It’s also true that permanent ketosis may not suit everyone. However, there is a way to build a sustainable keto diet which utilizes intermittent, cyclical ketosis as opposed to long-term ketosis…
A ketogenic diet also has been shown to improve blood sugar control for patients with type 2 diabetes, at least in the short term. There is even more controversy when we consider the effect on cholesterol levels. A few studies show some patients have increase in cholesterol levels in the beginning, only to see cholesterol fall a few months later. However, there is no long-term research analyzing its effects over time on diabetes and high cholesterol.
The first modern study of fasting as a treatment for epilepsy was in France in 1911.[12] Twenty epilepsy patients of all ages were "detoxified" by consuming a low-calorie vegetarian diet, combined with periods of fasting and purging. Two benefited enormously, but most failed to maintain compliance with the imposed restrictions. The diet improved the patients' mental capabilities, in contrast to their medication, potassium bromide, which dulled the mind.[13]
I ate a lot of bacon, cheese, eggs and meat (steak and chicken mostly). For a person whose eating philosophy is typically more plant-based and whole-food-focused, eating processed pork products every morning took a lot of personal persuasion. It also took a complete mental shift, because eating multiple pieces of bacon every day for weeks on end goes against everything I've been taught for personal health.
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