Was this site produced by the same folks who translated the Hungarian phrase meaning 'Can you direct me to the station? as ‘Please fondle my bum’?
The Germany section seems to be a bit dated (on manners, role of women, etc. by some 2-3 decades). One gesture mentioned (the two-fisted one) is unknown to me.
For business purposes I consider this site to be more accurate. (The site seems to be targeted at a truly worldwide audience so it expressly mentions some things that are pretty universal in modern European/North American cultures but maybe not in others.)
I suspect the author referred to heaping food on one’s plate and then not eating up (what Germans refer to as the eyes having been larger than the stomach).
That’s actually not an absolute rule, Mr. F. Of course any really serious topic is a perilous one in conversation, but where pertinent (and not gratuitous, like usually in the British press 
) it’s mentionable.