Business Travel -vs- Diet, who wins?

Business trips are a huge pot-hole for me. I frequently travel for my job and several are to be a speaker/presenter. Situations where people try to be a good host and treat me to a big breakfast, lunch, and dinner. A single day of this can set me back 3 or 4 days worth of progress. I can steer towards lo-cal options but many times they are not available or more cals than I am used too. Further, when I actually get into a nice restaurant I find a good glass of wine and meal very tempting. This creates a strong conflict between weight goals and spending valuable time with clients and co-workers.
I hate being dishonest, but am tempted to say I don't feel well and choose not to eat. That is easier than saying I'd rather loose weight than spend time with you.
I have several trips coming up in April and would love to get some advice on what has worked for others.
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