Undermining your efforts isn't going to help. A VLCD can produce some big changes very quickly - we have to get used to that but maybe we don't take into account our partners do too. Maybe they're not ready for that rapid change or simply like us the way we are ... it's a comfort zone and our lack of confidence means we stay out of the limelight. Maybe they worry about what could happen if we step IN to the limelight.
There could be a variety of reasons why he said what he did but you need to sit down and have a talk with him about how much you want this and how it'll benefit your health in the long run. I've heard of men sabotaging their partners' efforts by coercing them into eating etc. Just be aware of the possibility and consider his motives if he starts chipping away at your resolve - he's just scared of the unknown.