6 . Hellerstein MK. De novo lipogenesis in humans: metabolic and regulatory aspects. Eur J Clin Nutr. 1999 Apr; 53 Suppl 1: S53-65. 7 . Acheson KJ, Schutz Y, Bessard T, et al. Glycogen storage capacity and de novo lipogenesis during massive carbohydrate overfeeding in man. Am J Clin Nutr. 1988 Aug; 48 (2): 240-47. 8 . Minehira K, Bettschart V, Vidal H, et al. Effect of carbohydrate overfeeding on whole body and adipose tissue metabolism in humans. Obes Res. 2003 Sep; 11 (9): 1096-1103. 9 . McDevitt RM, Bott SJ, Harding M, et al. De novo lipogenesis during controlled overfeeding with sucrose or glucose in lean and obese women. Am J Clin Nutr. 2001 Dec; 74 (6): 737-46. 10 . Dirlewanger M, di Vetta V, Guenat E, et al. Effects of short-term carbohydrate or fat overfeeding on energy expenditure and plasma leptin concentrations in healthy female subjects. Int J Obes Relat Metab Disord. 2000 Nov; 24 (11): 1413-18. 11 . McDevitt RM , Bott SJ, Harding M, et al. De novo lipogenesis during controlled overfeeding with sucrose or glucose in lean and obese women. Am J Clin Nutr. 2001 Dec; 74 (6): 737-46. 12 . Danforth E Jr. Diet and obesity. Am J Clin Nutr. 1985 May; 41 (5 Suppl): 1132-45. 13 . Hellerstein MK. No common energy currency: de novo lipogenesis as the road less traveled. Am J Clin Nutr. 2001 Dec; 74 (6): 707-8.
You must have a strange view of "normal conditions." Fat is actually a more-efficient, longer lasting source of energy than carbohydrates.
>De novo lipogenesis in humans: metabolic and regulatory aspects. http://www.ncbi.nlm.nih.gov/pubmed/10365981
"Eucaloric replacement of dietary fat by CHO does not induce hepatic DNL to any substantial degree. Similarly, addition of CHO to a mixed diet does not increase hepatic DNL to quantitatively important levels, as long as CHO energy intake remains less than total energy expenditure (TEE)."