High CGA Instant Coffee for High Potency Fat Loss: Visceral and Total Fat Loss Increase 6-9-fold 😮, But...

"The number of subjects (71 subjects/group) was calculated on the basis of the assumption of a change in VFA (ΔVFA) of 5 cm², standard deviation of 15 cm², significance level of α = 0.05, and power (1 − β) = 0.80. To account for the potential for dropouts, the target number of subjects was set at 150" (Watanabe 2019). 

Moreover, the trial was registered at www.umin.ac.jp/ctr/ as UMIN000036011. Now, none of these parameters guarantee that the study is unbiased, objective, practically relevant, etc. but trial registration, power calculations, inclusion of only "healthy" overweight subjects, a study duration of 12 weeks, dietary control that shows a lack of differences between the two study groups (see Table 1) are indicators of study quality and real-world relevance of a study you will certainly see being referred to in adds for the instant coffee I previously labeled as "high octane coffee".
Only a single serving did the trick! All instant coffee was consumed (only) once daily for 12 weeks, with four-week pre- and post-observation periods. Abdominal fat area and anthropometric measurements were analyzed at baseline and at four, eight, and 12 weeks, and 142 subjects completed the study - that's pretty much in line with what the power-analysis suggested to be necessary.

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Table 1: Dietary intake at 0 and 12 weeks in control and CGA groups. Data are presented as mean ± SD. Control (n = 70), CGA (n = 72). Group represents p-value in effect of group. Time represents p-value in effect of time. Group × time represents p-value in effect of group × time interaction - all analyses by repeated-measures ANOVA (Watanabe 2019).

In conjunction with the absence of dietary changes illustrated in Table 1 (obviously the study wasn't as controlled as a metabolic ward study), the weight ... ah, I should say fat loss effects of the elevated CGA intake was quite impressive: The absolute values and changes from baseline in visceral (#VFA), subcutaneous (#SFA), and total (#TFA) fat area are shown in Table 2.
(Watanabe 2019)

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Table 2: Changes in physical assessment parameters in control and CGA groups (

As the authors point out, "[t]he CGA group exhibited a significant decrease relative to the control group at 12 weeks by t-test in VFA (CGA group: −9.0 cm², control group: −1.0 cm², p = 0.025) and changes in VFA from baseline, i.e., ΔVFA (p < 0.001)" (Watanabe 2019). In plain English:

Even in the absence of a meaningful conscious (or at least detectable) reduction in energy intake, a single cup of the high octane coffee shed 9.0 cm² visceral, i.e. metabolically particularly unhealthy fat - that's 9x more than the obviously non-significant -1.0 cm² the subjects in the control group dropped on their 12-week journey.
In contrast to what the FT of the study seems to suggest (there it says: "[t]he change in the TFA from baseline (ΔTFA) was significantly smaller [sic!] in the CGA group compared with the control group at 12 weeks" | Watanabe 2019), the significant group × time interaction (p = 0.001) and the group effect (p < 0.001) the scientists observed for the total body fat area (see Table 2 #TFA) clearly favored the CGA coffee of which I am not even sure that it's already on the market, as well.

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Figure 1: My plot of the absolute visceral (#VFA) and subcutaneous (#SFA) development in Watanabe 2019 shows: inter-group comparisons as I present them in the headline and relative changes as presented in the arrow an easily mislead you to overestimate the practical (in mirror) significance of the results.

Against that background, it doesn't come as a surprise that the CGA subjects also lost more body weight, BMI, and inches off their waists (#BW, #BMI, #WC | p = 0.025, p = 0.015, p = 0.001, respectively); a result the authors provide some additional substance to, when they write...

"[...] Δweight, ΔBMI, and ΔWC in the CGA group had a significant group × time interaction compared with the control group by repeated-measures ANOVA (p = 0.010, p = 0.006, and p = 0.012, respectively). Moreover, a significant group effect was detected for ΔWC (p = 0.023); i.e., WC in the CGA group was significantly decreased (0.8 cm) relative to that in the control group at 12 weeks (p = 0.001, t-test). With respect to Δweight and ΔBMI, the CGA group showed a decreasing trend relative to the control group (p = 0.080 and p = 0.071, respectively)" (Watanabe 2019).

References:

• Fung, Kenneth, et al. "9 Effect of coffee consumption on arterial stiffness from UK biobank imaging study." (2019): A8-A10.
• Marventano, Stefano, et al. "Coffee and tea consumption in relation with non-alcoholic fatty liver and metabolic syndrome: A systematic review and meta-analysis of observational studies." Clinical nutrition 35.6 (2016): 1269-1281.
• Mure, Kanae, et al. "Habitual coffee consumption inversely associated with metabolic syndrome-related biomarkers involving adiponectin." Nutrition 29.7-8 (2013): 982-987.
• Kajikawa, Masato, et al. "Coffee with a high content of chlorogenic acids and low content of hydroxyhydroquinone improves postprandial endothelial dysfunction in patients with borderline and stage 1 hypertension." European journal of nutrition 58.3 (2019): 989-996.
• Ochiai, Ryuji, et al. "Effects of hydroxyhydroquinone-reduced coffee on vasoreactivity and blood pressure." Hypertension Research 32.11 (2009): 969.