High-protein ketogenic diet (HPKD): This version of the keto diet is often followed by folks who want to preserve their muscle mass like bodybuilders and older people. Rather than protein making up 20 percent of the diet, here it’s 30 percent. Meanwhile, fat goes down to 65 percent of the diet and carbs stay at 5 percent. (Caution: folks with kidney issues shouldn’t up their protein too much.)
The most common and relatively minor short-term side effects of ketogenic diet include a collection of symptoms like nausea, vomiting, headache, fatigue, dizziness, insomnia, difficulty in exercise tolerance, and constipation, sometimes referred to as keto flu. These symptoms resolve in a few days to few weeks. Ensuring adequate fluid and electrolyte intake can help counter some of these symptoms. Long-term adverse effects include hepatic steatosis, hypoproteinemia, kidney stones, and vitamin and mineral deficiencies.
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:
The importance of dietary CHO is so well ingrained that the concept is taken for granted. In fact, basic macronutrient guidelines are predicated upon the idea that the central nervous system (CNS) requires a minimum of ~130 grams (~520 kcal) per day to function properly (i.e., to maintain optimal cognitive function). As a result, the minimum recommended daily intake of CHO reflects this idea (7). Similarly, most contemporary texts on sports nutrition emphasize the outsized role of CHO in optimizing both athletic performance and recovery (9). Frequently referred to as the “master fuel,” recommendations range from 3 – 12 grams per kilogram of bodyweight, per day. As an example, the recommended daily intake for a 180-lb athlete would be 246 – 982 grams, with a caloric equivalent of 984 – 3,928 calories. In marked contrast, the KD would recommend a maximum of just 50 grams (~ 200 calories) per day for the same individual.
By discriminating the components of the FFM as determined by DXA, it was observed that these variations were mainly due to changes in lean mass, whereas bone mineral content remained unchanged from baseline (0.003 ± 0.066 kg at visit C-2; −0.018 ± 0.066 kg at visit C-3; and −0.028 ± 0.066 kg at visit C-4; P > 0.05). Given that DXA technique is unable to discriminate the composition of lean mass, the question was raised as to whether the observed reductions in lean mass were at the expense of muscle mass or body water content. Therefore, further analysis was performed by MF-BIA , which is able to discriminate these 2 variables. Remarkably, the measurements performed by MF-BIA showed that the initial loss of FFM at visit C-2 (−3.1 ± 1.5 kg) was mostly due to total body water loss (−2.3 ± 1.1 kg), both intra- (−1.5 ± 0.7 kg) and extracellular [−0.8 ± 0.5 kg; Fig. 3(B)], probably because of the intense diuresis that occurs in the first phase of any VLCK diet. In subsequent visits, a slight recovery of intra- and extracellular water was observed, similar to the recovery observed with total FFM. This means that reductions attributable to muscle mass were, depending on the method used, around 1 kg throughout the 4-month study; only 5% of the total 20.2 kg of weight lost was FFM.
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).
Ketones are a very effective fuel for the brain—often a more efficient fuel than glucose. Your body is like a hybrid car when it comes to fuel. When you run out of carbohydrates to burn for fuel—say you’re fasting before a surgery or a religious holiday—your body seeks an alternative way to get more fuel. (If your body didn’t do this, you would die after a short fast.) So the body kicks into burning fat, which is the metabolic state of ketosis, or “keto.” Technically, your liver takes long-chain and medium-chain fatty acids from your fat tissue, and produces a major ketone called beta-hydroxybutyrate (BHB). BHB provides more energy per unit oxygen used than glucose, which benefits the brain.

Many versions of ketogenic diets exist, but all ban carb-rich foods. Some of these foods may be obvious: starches from both refined and whole grains like breads, cereals, pasta, rice, and cookies; potatoes, corn, and other starchy vegetables; and fruit juices. Some that may not be so obvious are beans, legumes, and most fruits. Most ketogenic plans allow foods high in saturated fat, such as fatty cuts of meat, processed meats, lard, and butter, as well as sources of unsaturated fats, such as nuts, seeds, avocados, plant oils, and oily fish. Depending on your source of information, ketogenic food lists may vary and even conflict.
The ketogenic diet has been studied in at least 14 rodent animal models of seizures. It is protective in many of these models and has a different protection profile than any known anticonvulsant. Conversely, fenofibrate, not used clinically as an antiepileptic, exhibits experimental anticonvulsant properties in adult rats comparable to the ketogenic diet.[58] This, together with studies showing its efficacy in patients who have failed to achieve seizure control on half a dozen drugs, suggests a unique mechanism of action.[56]

“As a nephrologist, I have seen many patients with end-stage kidney failure resulting from diabetes and obesity. I decided to switch my career towards wellness, integrative medicine and obesity management. I now provide guidance for ketogenic and low-carb diets along with fasting to all patients in my clinic and via telehealth consultations. It is very rewarding to see their health improve and their medications reduced or eliminated. I refer all my patients to Diet Doctor on the first visit and I teach them also to use the recipes on the site. Thank you for providing an unbiased educational platform!”

A randomized control study in 2017 examined the effects of a ketogenic diet combined with Crossfit training on body composition and performance. Results from this study concluded that subjects following a low-carbohydrate ketogenic diet (LCKD) significantly decreased body weight, body fat percentage and fat mass compared to those in the control group[*].
At 469 pounds I restricted myself to a daily calorie intake between 1k-1.5k a day. Often I would even go down to 800 (not advocating this!). Well, i'm still alive today, down a ton of weight and I restrict myself to about 1.5-2k per day now. As others said, calorie restriction is required to lose, but generally speaking I just go by how I feel. If im full of energy, feeling great and not hitting my calories it's not really a big deal to me.
The average daily goal for keto is 20 grams of net carbs. Net carbs are the total carbs in a given serving of food, minus the carbohydrates that are supplied by fiber. You’ll find carb grams quickly add up, even when you’re choosing the best low-carb foods, like spinach and avocado. Keeping your body in a quasi-keto state can be hard on you, warns Santo: “This will leave you feeling sluggish, foggy, and discouraged,” he says. “It will most likely cause a weight plateau, and maybe even weight gain.” Here’s what it’s really like to be on a keto diet.