Run by the Charlie Foundation, this calculator can be helpful when you’re using keto as a therapy to help manage a medical condition. The calculator helps estimate calorie needs based on weight, assists in determining a macro ratio and macros needed per meal, and can calculate macro numbers on the basis of meals and snacks you enter into the system. Also takes into account fluids, supplements, and medications.
There exists great debate on how to quantify the macronutrient ratios and percentages for a traditional ketogenic diet. Despite numerous opinions, the common and ultimate objective is to develop a diet that is sustainable in achieving the desired outcome (i.e., a state of ketosis). As such, while it is suggested that 65–80% of the total calories come from fat, and 15–30% from protein, these numbers will be optimized according to every individual’s unique metabolic needs. For example, an individual who is trying to achieve a state of ketosis might have a different ratio of macronutrient requirements than someone who is using a ketogenic diet to improve their body composition. Once the body begins to use fat as its primary fuel source, metabolic “keto-adaptation” characterized by increased production of ketones takes place. It is important to note that there is no “optimal” level of ketosis, nor is there a standard macronutrient profile to achieve a ketogenic state, because factors such as activity level, body composition, and desired health and performance outcomes will influence these variables. Although individualized, currently offers a Keto Calculator that can help provide you with a starting point on your macronutrients.
Aude, Y., A. S, Agatston, F. Lopez-Jimenez, et al. “The National Cholesterol Education Program Diet vs a Diet Lower in Carbohydrates and Higher in Protein and Monounsaturated Fat: A Randomized Trial.” JAMA Internal Medicine 164, no. 19 (2004): 2141–46. doi: 10.1001/archinte.164.19.2141.
This can look different for everybody, but some popular forms of this are the 16:8 diet, where you fast for 16 hours (usually from dinnertime until a late breakfast) and eat all your food within an eight-hour span. Another is the 5:2 diet, where you eat less than 500 calories for two non-consecutive days a week and then eat normally for the rest of the week.
The confusion between ketosis and ketoacidosis is a prominent reason why many individuals, particularly doctors, steer clear of the keto diet for beginners. It’s important to understand that these are two very DIFFERENT metabolic states. Ketoacidosis may occur in uncontrolled type 1 diabetics (DKA; diabetic ketoacidosis) due to insulin deficiencies. DKA is associated with both elevated blood glucose and ketone levels; due to little to no insulin production, blood glucose cannot enter insulin-dependent cells to be used for energy, and as such, cells become hungry, resulting in uncontrolled ketone production. In turn, a highly acidic environment is created that can have detrimental effects on an individual’s health, possibly resulting in death. It must be echoed that the ketogenic diet, which induces “nutritional” ketosis, is vastly different and should never be confused with DKA. To put this in perspective, a normal state of ketosis, as achieved via the keto diet for beginners may elevate ketones anywhere from 0.3–5mM, while DKA results in ketone levels of about 15mM or higher.
The ketogenic diet is calculated by a dietitian for each child. Age, weight, activity levels, culture, and food preferences all affect the meal plan. First, the energy requirements are set at 80–90% of the recommended daily amounts (RDA) for the child's age (the high-fat diet requires less energy to process than a typical high-carbohydrate diet). Highly active children or those with muscle spasticity require more food energy than this; immobile children require less. The ketogenic ratio of the diet compares the weight of fat to the combined weight of carbohydrate and protein. This is typically 4:1, but children who are younger than 18 months, older than 12 years, or who are obese may be started on a 3:1 ratio. Fat is energy-rich, with 9 kcal/g (38 kJ/g) compared to 4 kcal/g (17 kJ/g) for carbohydrate or protein, so portions on the ketogenic diet are smaller than normal. The quantity of fat in the diet can be calculated from the overall energy requirements and the chosen ketogenic ratio. Next, the protein levels are set to allow for growth and body maintenance, and are around 1 g protein for each kg of body weight. Lastly, the amount of carbohydrate is set according to what allowance is left while maintaining the chosen ratio. Any carbohydrate in medications or supplements must be subtracted from this allowance. The total daily amount of fat, protein, and carbohydrate is then evenly divided across the meals.[37]
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]

Achieving optimal ketosis hinges on finding the right balance of macronutrients (or “macros” in keto-speak); these are the elements in your diet that account for the majority of your calories, a.k.a. energy—namely, fat, protein, and carbohydrates. By the way, it’s often “net grams” of carbohydrates that are counted toward your daily intake; “net” deducts the amount of fiber in a food from its carbohydrate total.