MU. Yang and TB. Van Itallie (1976). Composition of weight lost during short-term weight reduction. Metabolic responses of obese subjects to starvation and low-calorie ketogenic and nonketogenic diets. The Journal of clinical investigation, 58(3), 722-30. https://doi.org/10.1172/JCI108519

PubMed 956398

[Abstract]
The effects of starvation, an 800-kcal mixed diet and an 800-kcal ketogenic (low carbohydrate-high fat) diet on the composition of weight lost were determined in each of six obese subjects during three 10-day periods. The energy-nitrogen balance method was used to quantify the three measurable components of weight loss; protein, fat, and water. On the 800-kcal ketogenic diet, subjects lost (mean +/- SE) 466.6 +/-51.3 g/day; on the isocaloric mixed diet, which provided carbohydrate and fat in conventional proportions, they lost 277.9+/- 32.1 g/day. Composition of weight lost (percentage) during the ketogenic diet was water 61.2, fat 35.0, protein 3.8. During the mixed diet, composition of loss was water 37.1, fat 59.5, protein 3.4...