Indeed it is. What is important however is whether the information is true, and not his own diet or appearance. The below is from a 2017 review article from the European Heart Journal (https://bit.ly/EHJ2017).

"Critics have noted that some of the dietary data from Greek cohorts, which experienced very low rates of CVD, were collected during Lent, thus potentially falsely deflating the proportion of calories from saturated fat and animal products.5 However, SCS data collected during and outside of the fasting period were compared.7 No significant differences were seen between Lenten and non-Lenten dietary patterns in either Greek cohort. Further, habitual dietary data collected by the SCS researchers were consistent with dietary intake data collected by an unaffiliated study on diet in Greece conducted in 1948, further suggesting that SCS data were not distorted by Lent.27–29

And now unfortunately, Greece has one of the highest rates of CVD in the EU (https://bit.ly/CVDGreece)