Gaining Weight on Keto: Real Cases, Foods and Practical Insights

Published case reports offer useful examples of weight restoration on keto. They also show why food intake, individual needs and clinical support matter more than following a fixed formula.

A ketogenic diet can be compatible with weight gain. The evidence reviewed here includes five detailed clinical histories and seven additional people reported to have gained weight in a supervised trial.

These are 12 documented weight-gain observations, rather than 12 separate, fully described case studies. Most concern anorexia nervosa, so they cannot establish how well the same approach works for otherwise healthy adults who want to gain weight.

For someone choosing keto for a therapeutic reason, the useful question is how to support adequate nourishment while preserving the benefit they are seeking. The following examples offer starting points for that discussion, rather than a universal weight-gain protocol.

Three cases of weight restoration on animal based keto

A 2023 retrospective series described three adults with anorexia nervosa. The names below are published pseudonyms. [1]

Katherine

Food and protocol: Fatty beef, lamb, fish, bacon, egg yolks and organs; approximately 2,000–2,500 kcal daily at follow-up. Timeline and outcome: She gained 9 kg in four months and later maintained approximately 54 kg for two years. Her historical lowest weight was 32 kg.

Problems and response: No specific digestive disorder or digestive treatment was reported. Anxiety about higher-calorie eating eased as intake increased. Osteoporosis remained documented at follow-up; endocrinology and psychiatry reviews continued. Weight recovery did not mean every medical problem had resolved. [1]

Trevor

Food and protocol: Approximately 75% of energy from fat, blood ketones above 1 mmol/L; eggs, butter, milk, fatty meat or fish and added animal fats. Timeline and outcome: He reached 64 kg and maintained it for over a year. His historical lowest weight was 39.9 kg, before keto began.

Problems and response: No specific digestive problem was reported. Food-related anxiety, binge–restrict cycles and compulsive exercise had obstructed recovery. He reported less anxiety after the dietary change and shifted to weightlifting three days weekly, with ketogenic nutritionist follow-up. [1]

Meal timing: The example menu describes breakfast and dinner. Exact times, snacks and a fixed eating window were not reported; this does not establish that he ate only twice daily. [1]

Amelia

Food and protocol: Approximately 3,000 kcal daily, mainly fatty red meat, fish and animal fats. Timeline and outcome: BMI rose to 18.5 during the year she changed her diet; reported remission continued for almost five years. Her historical lowest BMI was 11.8.

Problems and response: Vegetables caused gastrointestinal distress, so she avoided them. The report does not specify symptoms, diagnostic testing or a separate digestive treatment.

She gradually introduced animal proteins and reported improved psychiatric symptoms as meat and fat intake increased. [1]

What this means for you: These recoveries unfolded over months and years. The lowest weights reported occurred before keto began, so the full recovery cannot be counted as weight gained on keto. Progress is best understood from the starting point of each intervention.

The food lists also illustrate variety within an animal-based approach. They do not establish that any individual food is essential. A published menu is a description of what someone ate, not a prescription to copy.

Weight gain with keto and additional psychiatric treatment

A 2020 report followed a 29-year-old woman with longstanding anorexia nervosa who was already within the normal BMI range when ketogenic treatment began. [2]

Food and protocol: A dietitian-supported diet using a fat-to-protein-plus-carbohydrate ratio of 1:1 to 2:1 by weight. Foods included bacon, eggs, cheese, avocado and MCT oil, alongside high-fat meals and smoothies. Breath acetone was checked two or three times weekly.

Timeline and outcome: After three months of keto, she received four ketamine infusions over two weeks. The paper’s table records 57.2 kg immediately before keto, 58.9 kg around ketamine treatment and 61.7 kg three months afterwards: a gain of approximately 4.5 kg across the combined treatment. Remission was reported beyond six months. The narrative gives slightly different weights.

Practical insight: This is a combined-treatment case. It shows that weight gain can occur while eating keto, but it cannot establish that keto alone produced either the gain or psychiatric recovery. [2]

Problems and response: The report does not identify a pre-existing digestive disorder. Mild nausea occurred after the first ketamine infusion. Subsequent infusions were preceded by prescribed ondansetron, with no further reported nausea. This addressed a treatment side effect, not fat intolerance.

Persistent anorexic compulsions after three months of keto prompted the addition of ketamine; supportive psychotherapy continued afterwards. [2]

Weight gain during ketogenic treatment for epilepsy

A 2013 report included a 10-year-old boy with severe neurological impairment, epilepsy and a gastrostomy feeding tube. He began at 30 kg with a BMI of 14. [3]

Food and protocol: Tube-fed ketogenic nutrition, initially at a 3:1 fat-to-protein-plus-carbohydrate ratio and 1,250 kcal daily. The paper does not specify the formula or ingredients. Clinicians later increased the ratio to 4.7:1 and intake to 1,994 kcal daily.

Timeline and outcome: Weight reached 33 kg after six months. Following an infection-related period of difficulty maintaining ketosis, weight eventually increased from 34 kg to 50.8 kg over the next 3.5 years, while height also increased.

Practical insight: This was paediatric growth during complex medical treatment, not an adult muscle-building programme. It demonstrates the need to adjust nutrition over time rather than assume a single calorie target will remain appropriate. [3]

Problems and response: No specific digestive disorder or treatment was described. Feeding was delivered through a gastrostomy tube. A prolonged bacterial infection coincided with difficulty maintaining ketosis and slower weight gain; clinicians increased the ketogenic ratio and later calories to support growth.

Seven further weight gains in a supervised trial

A 2026 single-arm feasibility trial studied adults with anorexia nervosa who were mildly underweight or weight-restored.

Eighteen completed 14 weeks; seven gained 1.2–8.7 kg, six stayed within 1 kg of baseline and five lost 2.7–4.3 kg. Average gain was 0.5 kg. [4]

Protocol: Three meals and two snacks daily; targets of 70% fat, 20% protein and 10% carbohydrate by energy. Participants received ketogenic meals or prepared their own with dietitian guidance.

Blood ketones were monitored, targeting 0.5–3 mmol/L, alongside weekly weight and clinical reviews. Those losing weight were instructed to eat more.

Problems and response: Across the trial, mild nausea, constipation and dehydration were reported; side-effect reports declined from 40% initially to none at study end.

The publication does not assign these problems to the seven people who gained weight or specify individual digestive remedies. Some participants needed extensive coaching for anxiety about eating and adequate intake.

Dietitian and psychiatric support, personalised meals and instructions to eat more when losing weight were documented. Symptom improvement does not establish which measure resolved a digestive complaint. [4]

Meal timing: Three meals and two snacks daily were prescribed. No fixed clock times or time-restricted eating window were specified. [4]

Practical insight: A structured eating pattern is worth discussing when meals are easily missed. However, this trial does not identify an optimal weight-gain menu or prove that ketosis caused the gains. The people who lost weight belong in the interpretation too.

What these examples can teach us

These reports support a modest conclusion: gaining weight while following a ketogenic diet is possible. They do not establish keto as the best diet for weight gain, nor do they identify a single successful ratio of fat, protein and carbohydrate.

For a personalised plan, first define what success means. Restoring weight after illness, gaining muscle, supporting growth and maintaining a comfortable weight are different goals. A rising scale reading alone does not tell us which tissues have increased or whether health has improved.

Consider what you can consistently eat and digest. Your appetite, meal frequency, early fullness, food tolerances and activity all matter, as does the effort of preparing meals. A ketogenic menu needs to be comfortable and practical enough to sustain.

Track your progress alongside how you feel. Record your weight trend, digestion, strength, wellbeing and any changes to your meals. Note when you make an adjustment and give it time to assess the response. This can help you and your practitioner identify a sustainable approach.

Clinical context matters

The anorexia cases describe an experimental approach in a condition requiring specialist care. They should not be used as instructions for self-treating an eating disorder or severe underweight.

Significant malnutrition can involve refeeding risk when intake increases, and care should be coordinated with an appropriate medical and eating-disorder team. [5, 6]

For other adults, ongoing unintended weight loss deserves assessment rather than repeated dietary restriction. A weight-gain plan should address the reason for the loss and the person’s nutritional needs, alongside any reason for continuing ketogenic therapy. [5]

Building an approach around the individual

A useful ketogenic weight-gain plan begins with the person: their goal, health, appetite, digestion, activity and response to food. These case reports provide examples to investigate, not a template everyone must follow.

At Oak Keto Nutritionist, I help people consider how ketogenic nutrition can fit their individual goals and circumstances. If you want to discuss weight stability or weight gain while following keto, you can start with a free discovery call or email.

References

[1] Norwitz NG, Hurn M, Espi Forcen F. Animal-based ketogenic diet puts severe anorexia nervosa into multi-year remission: A case series. Journal of Metabolic Health. 2023;6:a84. https://doi.org/10.4102/jir.v6i1.84

[2] Scolnick B, Zupec-Kania B, Calabrese L, Aoki C, Hildebrandt T. Remission from Chronic Anorexia Nervosa With Ketogenic Diet and Ketamine: Case Report. Frontiers in Psychiatry. 2020;11:763. https://doi.org/10.3389/fpsyt.2020.00763

[3] Olmez I, Montgomery M, James KC, Pina-Garza JE. The Ketogenic Diet–Induced Weight Gain With Decreased Energy Consumption. ICAN Infant Child and Adolescent Nutrition. 2013;5(1):29–31. https://doi.org/10.1177/1941406412461375

[4] Frank GKW, Scolnick B, Beckwith C, et al. Symptom impact and safety of ketogenic therapy in adults with anorexia nervosa: a feasibility trial. Communications Medicine. 2026;6:315. https://doi.org/10.1038/s43856-026-01644-0

[5] NICE. Nutrition support for adults. CG32. https://www.nice.org.uk/guidance/cg32/chapter/Recommendations

[6] NICE. Eating disorders recognition and treatment. NG69. https://www.nice.org.uk/guidance/ng69/chapter/recommendations