Hungrier? Exercising in much colder temperatures

[Eden]

Pretty sure that is actually that is incorrect.... You don't burn significantly more when it's cold. I haven't found the full study that I read yet, but here is a summary of one that is, if not the same one, similar.

Many people feel extremely hungry after immersion in cold water. As a result they simply replace all the calories they’ve burned with a large post-exercise meal, completely wiping out any potential weight loss benefits of the swimming.

In a University of Florida study, a group of men exercised for 45 minutes in both neutral (33 degrees Celsius) and cold (20 degrees Celsius) water temperatures. They were then allowed to eat as much food as they wanted.

The men burned a similar number of calories in the cold and neutral water conditions, averaging 505 and 517 calories, respectively. However, calorie intake after exercise in the cold water averaged 877 calories, which was 44% more than for the neutral temperature.

Granted the 10% your coach recommends isn't a huge amount more intake, but certainly much more than the difference in what was observed, which was only around 2% more, 10-12 calories, not 50.