Calculate Your Keto Macros
A well-formulated ketogenic diet is a metabolic intervention, not just a low-carb meal plan. The macronutrient split that defines nutritional ketosis in adults is generally carbohydrates below 50 g per day (often under 25 g for therapeutic targets), protein around 1.2 to 1.7 g per kg of reference body weight (roughly 20 to 25 percent of calories), and fat filling the remainder at about 70 to 75 percent of calories. The biological endpoint is sustained beta-hydroxybutyrate (BHB) above 0.5 mmol/L on a blood ketone meter, the threshold that Stephen Phinney and Jeff Volek call nutritional ketosis (0.5 to 3.0 mmol/L). That is a meaningfully different state from the classic 4:1 ketogenic ratio used for refractory pediatric epilepsy, the Modified Atkins Diet (MAD) used as a less restrictive epilepsy alternative, or cyclical (CKD) and targeted (TKD) variants popular with strength athletes. This calculator lets you set your daily calorie target and goal (cut, maintain, or lean gain) and returns the gram targets for fat, protein, and carbs that keep you inside nutritional ketosis while honoring an evidence-based protein floor for lean mass retention. Values reflect 2026 clinical literature and are reviewed periodically.
When to use this calculator
- Type 2 diabetes remission protocols (Virta-style continuous remote care with BHB targeting and HbA1c monitoring)
- Adjunctive therapy for drug-resistant epilepsy in adolescents and adults using a Modified Atkins approach instead of a strict 4:1 classical keto ratio
- Endurance and CrossFit athletes targeting fat adaptation with BHB in the 0.8 to 1.5 mmol/L range for steady-state performance
- Weight-loss plateau breaks for low-carb dieters who have stalled on a generic low-carb plan and need a true sub-50 g carb threshold
- Lean-mass preservation during an aggressive cut (20 to 25 percent deficit) where a 1.6 g/kg protein floor matters more than the fat ratio
- PCOS and insulin resistance management where lower carb intake reduces postprandial insulin response
- Cognitive support protocols (mild cognitive impairment, migraine prevention) where therapeutic BHB above 1.0 mmol/L is the goal
- Fitness professionals and dietitians validating client targets before building a meal plan
Calculation Example
- 2,000 kcal with weight loss goal
- 155g fat
How it works
3 min readKetogenic eating is a metabolic intervention. The point is not the macro ratio itself but the downstream state — sustained nutritional ketosis with BHB between 0.5 and 3.0 mmol/L, the range Stephen Phinney and Jeff Volek describe in The Art and Science of Low Carbohydrate Living as the foundation of a well-formulated ketogenic diet. The calculator translates that target into grams of fat, protein, and carbohydrate for the calorie ceiling you give it.
How the Math Works
Worked example for a 180-lb (82 kg) trainee on a moderate cut. Estimated TDEE is roughly 2,500 kcal, deficit target is 2,000 kcal. The split looks like this:
| Macro | Grams | kcal | % of calories |
|---|---|---|---|
| Carbohydrates | 25 g | 100 kcal | 5% |
| Protein | 130 g (~1.6 g/kg) | 520 kcal | 26% |
| Fat | 153 g | 1,380 kcal | 69% |
Protein is anchored to lean body mass to protect muscle during the deficit (0.6 to 0.8 g per pound of reference body weight, or 1.3 to 1.7 g per kg). Carbs are pinned at or below 25 g for a deeper therapeutic target. Fat fills the remaining energy. Push fat too high to chase a 75 percent ratio and you eat into the deficit; trim it too low and you stall ketosis.
Keto Adaptation and the "Keto Flu"
Full keto adaptation takes two to six weeks. The first week is when most people quit — headaches, lightheadedness, leg cramps, and bonk-level fatigue. This is sodium and water loss, not a metabolic problem. Standard mitigation protocol per Phinney/Volek and the Virta Health clinical guidelines:
Electrolyte loading is the single highest-leverage intervention for week-one adherence. Most failed keto starts are electrolyte failures, not willpower failures.
Measuring Ketosis
Urine ketone strips (Ketostix) measure acetoacetate excretion and become unreliable once you are fully adapted because the kidneys stop dumping ketones. The two reliable home methods in 2026:
Variants: MAD, CKD, TKD, and Classical Keto
The classical 4:1 ketogenic diet (4 g fat per 1 g of protein + carb combined, ~90 percent fat) is a therapeutic tool for pediatric epilepsy and is too restrictive for general use. The Modified Atkins Diet (MAD) is the adult-friendly version — 15 to 20 g carbs, liberal protein, fat ad libitum — and is the standard adult epilepsy protocol. Cyclical keto (CKD) layers a weekly 24- to 48-hour carb refeed onto a baseline keto week for glycogen-dependent strength athletes. Targeted keto (TKD) times 15 to 30 g of fast carbs around training. Low-carb/LCHF (Atkins-style, sub-100 g carbs) is not keto and will not produce sustained BHB above 0.5 mmol/L for most people.
Exogenous Ketones: Marketing vs Mechanism
BHB salts (Bevoke, Pruvit KetoOS) and ketone esters raise blood BHB acutely but do not replicate fat adaptation. They are useful for a single endurance event or to blunt acute keto-flu symptoms, but they do not accelerate adaptation and will not produce the metabolic flexibility that endogenous ketosis does. Most consumer products contain insufficient BHB per serving to reach therapeutic concentrations and have a price-per-mmol that is hard to justify outside specific use cases.
Clinical Outcomes
The strongest evidence is in type 2 diabetes. Virta Health's two-year outcomes (Athinarayanan et al., Frontiers in Endocrinology 2019; long-term follow-up published in Diabetes Therapy 2020) reported 53.5 percent diabetes reversal and 17.6 percent remission at two years on a continuous remote care model anchored to nutritional ketosis, with significant reductions in HbA1c, weight, and prescription medication burden. The ISSN position stand on diets and body composition lists ketogenic diets as effective for fat loss in calorie-matched comparisons, primarily through appetite suppression.
Risks to Flag
The most discussed 2026 concern is the LDL-C response. Norwitz, Soto-Mota, and colleagues (Current Opinion in Endocrinology, Diabetes and Obesity, 2022) characterized a "lean mass hyper-responder" phenotype — lean, athletic, metabolically healthy keto adopters who show large LDL-C and ApoB rises. Whether this elevation carries the same cardiovascular risk as the metabolic-syndrome phenotype is unsettled. If you start keto, baseline a full lipid panel (including ApoB) and recheck at three to six months. Other contraindications: pregnancy without supervision, type 1 diabetes without endocrinologist oversight (ketoacidosis risk), familial hypercholesterolemia, gallbladder disease history, and active eating disorders. This calculator is a planning tool, not medical advice.
Frequently asked questions
How many carbs can I eat on keto?
Total carbs below 50 g per day is the standard nutritional-ketosis ceiling. Many people need to drop to 20 to 25 g to consistently see BHB above 0.5 mmol/L. Track total carbs (not net) for the first month — fiber tolerance varies and the net-carb shortcut hides slip-ups.
How do I prevent the keto flu?
Front-load electrolytes from day one: 3 to 5 g sodium, 3 to 4 g potassium, and 300 to 500 mg magnesium daily. Salty broth twice a day handles most of the sodium. Drink to thirst, not to a gallon target — over-hydrating on top of low sodium makes symptoms worse. Symptoms usually resolve within 5 to 10 days.
What BHB level should I be targeting?
Phinney and Volek define nutritional ketosis as 0.5 to 3.0 mmol/L measured by blood BHB. For general fat loss and metabolic health, 0.5 to 1.5 mmol/L is fine. For therapeutic protocols (epilepsy, cognitive support, GLUT1 deficiency), clinicians often target 1.5 to 3.0 mmol/L. Above 3.0 mmol/L is unnecessary for most goals and can indicate overly aggressive fasting.
Is the LDL rise on keto dangerous?
It depends on phenotype. Norwitz and colleagues (Curr Opin Endocrinol Diabetes Obes 2022) described "lean mass hyper-responders" — lean, athletic adopters whose LDL-C and ApoB rise sharply. Whether this confers the same cardiovascular risk as LDL elevation in a metabolic-syndrome phenotype is unresolved in 2026. Pull a full lipid panel including ApoB at baseline and again at 3 to 6 months, and discuss results with a physician — especially if you have family history of premature ASCVD or familial hypercholesterolemia.
Cyclical keto vs strict keto — which is better?
Strict (continuous) keto produces the most consistent BHB and is the protocol used in clinical trials including Virta Health. Cyclical keto (CKD) layers a weekly 24- to 48-hour carb refeed and is mainly used by strength athletes whose glycogen demands exceed what gluconeogenesis can support. CKD breaks ketosis during the refeed window, so it is the wrong tool for therapeutic protocols. For most people pursuing fat loss or metabolic health, strict keto outperforms cyclical.
Can keto really reverse type 2 diabetes?
Reversal — defined as HbA1c below the diabetes threshold without glucose-lowering medication other than metformin — is supported by Virta Health's continuous remote care trial. Their two-year data (Athinarayanan et al., 2019; follow-up in Diabetes Therapy 2020) showed 53.5 percent diabetes reversal and 17.6 percent remission at two years, with broad reductions in HbA1c and medication use. The intervention is a structured medically-supervised nutritional ketosis program, not just "eat keto."
Do exogenous ketones (BHB salts, ketone esters) actually work?
They raise blood BHB acutely but do not replicate endogenous fat adaptation. Useful situational tools — a single endurance event, blunting acute keto-flu symptoms, a one-off cognitive demand — but they do not speed up adaptation and most consumer-grade BHB salts dose too low to reach therapeutic mmol/L levels. The price per mmol of elevation is steep. Spend the money on grass-fed beef and electrolytes first.
How much protein on keto — won't too much kick me out of ketosis?
The "protein kicks you out of ketosis via gluconeogenesis" idea is largely overstated. Gluconeogenesis is demand-driven, not supply-driven. The current standard is 1.2 to 1.7 g of protein per kg of reference body weight (about 0.6 to 0.8 g per pound) — enough to protect lean mass in a deficit. Going under that risks muscle loss; going meaningfully over (above 2.0 g/kg) is rarely needed and trades off against fat calories.
How is keto different from a standard low-carb or LCHF diet?
Low-carb / LCHF (Atkins-style, sub-100 g carbs) is a carbohydrate-restriction approach without a ketosis target. Keto specifically aims for sustained BHB above 0.5 mmol/L, which usually requires total carbs below 50 g and a high enough fat ratio to spare protein from gluconeogenic load. If you are not measuring BHB, you are doing low-carb, not keto.
Sources and references
- Virta Health — Two-Year Outcomes of a Novel Continuous Care Intervention for T2D
- Athinarayanan SJ et al. — Long-Term Effects of a Ketogenic Diet in T2D (Frontiers in Endocrinology 2019)
- Norwitz NG, Soto-Mota A et al. — Elevated LDL Cholesterol with a Carbohydrate-Restricted Diet (Curr Opin Endocrinol Diabetes Obes 2022)
- Phinney SD & Volek JS — The Art and Science of Low Carbohydrate Living (Beyond Obesity LLC)
- ISSN Position Stand: Diets and Body Composition (Aragon et al., JISSN 2017)