Can You Get Fat in Three Days? Study Shows Even W/ 1,500 Extra-Calories, You Can't. All But One Subject Actually Lost Some Body Fat During 3-Day Gluttony on >50% CHO Diets!

Be a glutton from time to time!

I know it goes against the holiday weight gain saga, but according to a recent study from the Fukuoka University in Japan (Sagayama. 2014), "[t]here was no significant difference in FM [fat mass] between the normal and overfeeding diets" in their latest study in the course of which they fed their healthy, non-obese Japanese men (age = 23.1 ± 1.6 years; height = 171.7 ± 3.6 cm; body weight = 63.6 ± 4.5 kg; and body mass index  =  21.6  ±  1.3  kg/m²) extra 1,500kcal per day.

Needless to say that you cannot expect the same benign effects in subjects suffering from chronic diseases and/or those who are already obese.
Several previous studies have suggested that an energy intake that exceeds the energy expenditure for 2 to 8 weeks led to increased fat mass (FM) (Levine. 1998; Lammert. 2000; Joosen. 2005) - with no difference depending on whether the energy came from fat or carbohydrates, by the way (see Lammert. 2000). Moreover, the concept of non-exercise activity thermogenesis (NEAT) seems important in energy balance regulation as in the study, which overfed 16 non-obese subjects with 4.2 MJ/day for 56 days; changes in NEAT directly predicted resistance to FM gain from overfeeding (Levine. 1998).

Additionally, there is an association between weight gain and sedentary time during 3 days of overfeeding (He. 2012). Thus, activity energy expenditure is the most important component of energy expenditure to maintain body weightand composition during overfeeding. However, there is little detailed evidence of changes in body composition when AEE is maintained during overfeeding.

In the study at hand, however, where the body composition was evaluated at three time points: the day before the 3-day normal diet of the survey period (Baseline 1st [BL 1st ]); the day after the 3-day normal diet of the survey period (this day is the same measurement before overfeeding) (Baseline 2nd (BL 2nd )); and the day after the overfeeding diet period (Overfeeding (OF)), the 1,500kcal the subjects could get from whatever they wanted to eat (ad libitum overfeeding - that's news) didn't have a significant impact on the body composition of the men (see Figure 4 at the bottom to see which macros were increased).
In addition to the researchers' exact measurements, the subjects measured their own body weights twice daily for the 6 days (in the morning fasting and again before going to bed) from BL 1st to OF.

Figure 1: Overview of the study design (Sagayama. 2014)

To make sure there was no crazy post-binge weight gain, the subjects who had to stick to their regular activity patterns and avoid vigorous exercise during the whole study period and a 2 months follow up (means I would not have participated ;) had to measure their own body weights (in the morning fasting) for 2 days during the postintervention observation period and for 2 weeks following completion of overfeeding phase, as well.
Sagayama et al. first evaluated body composition and measurement reproducibility. None of the classic determinants of body composition, i.e. body weight (-0.2 ± 0.5 kg, P= 0.17; % fat = -0.1 ± 0.5%, P= 0.49; FM = -0.1 ± 0.4 kg, P= 0.36; TBW = -0.1 ± 0.4 kg, P= 0.56; FFDS = 0.0 ± 0.4 kg, P= 0.71). Changed over the course / in response to the the three day overfeeding period (for the statistic nerds: The intraclass correlation coefficient for all body composition values was above 0.9 and the  coefficient variantion was less than 3%).

"Body weight, TBW, and FFDS increased during OF compared with BL 2nd measurements (Table 2 and Figures 2, 3, and 4; body weight = 0.7 ± 0.5 kg; TBW = 0.7 ±0.4 kg; FFDS = 0.0 ± 0.4 kg, P < 0.0001). There were no significant differences in FM and % fat between the BL 2nd and OF measurements (Table 2). Subjects measured their body weights during the postintervention period. All subjects returned to BL 2nd body weights within 2 weeks (5.0 ± 4.9 days)."

I know this sounds crazy, but if you take a closer look at the individual changes in body mass and body fat, you will see that the majority of subjects lost a minimal amount of body fat.

Figure 2: Body weight "gain" (mostly water; left) and fat loss (in all but two subjects; right) from baseline to post-overfeeding measurements (Sagayama. 2014)

The total body water, on the other hand, increased (for some subjects significantly) from baseline to post-overfeeding (+700g on average; data not shown in Figure 2).
References:

• Joosen, Annemiek MCP, Arjen HF Bakker, and Klaas R. Westerterp. "Metabolic efficiency and energy expenditure during short-term overfeeding." Physiology & behavior 85.5 (2005): 593-597.
• He, Jianying, et al. "Measurement of ad libitum food intake, physical activity, and sedentary time in response to overfeeding." PloS one 7.5 (2012): e36225.
• Lammert, Ole, et al. "Effects of isoenergetic overfeeding of either carbohydrate or fat in young men." British Journal of Nutrition 84.02 (2000): 233-245.
• Levine, James A., Norman L. Eberhardt, and Michael D. Jensen. "Role of nonexercise activity thermogenesis in resistance to fat gain in humans." Science 283.5399 (1999): 212-214.
• Saad, MOHAMMED F., et al. "Ethnic differences in sympathetic nervous system-mediated energy expenditure." Am J Physiol 261.6 Pt 1 (1991): E789-E794.
• Sagayama, Hiroyuki, et al. "Measurement of body composition in response to a short period of overfeeding." Journal of physiological anthropology 33.1 (2014): 29. 
• Schutz, Y., K. J. Acheson, and E. Jequier. "Twenty-four-hour energy expenditure and thermogenesis: response to progressive carbohydrate overfeeding in man." International journal of obesity 9 (1984): 111-114.
• Tappy, L. "Thermic effect of food and sympathetic nervous system activity in humans." Reproduction Nutrition Development 36.4 (1996): 391-397.
• Welle, S., and R. G. Campbell. "Stimulation of thermogenesis by carbohydrate overfeeding. Evidence against sympathetic nervous system mediation." Journal of Clinical Investigation 71.4 (1983): 916.