Overweight Boa Constrictor

Question
Hi,

I purchased a boa constrictor about a year ago, she is nearly 7 years old now but I have been unable to get her to lose weight, she is about 5 1/2 -6 foot long and weighs 5 1/2 kilos, the vets said she is overweight and to monitor her food and give her exercise regularly, before i got her she was being fed 2 medium rats every 7 days, I now feed her 1 large rat every 14 days, I did the change slowly in so her system could adapt, I also put her in the shower for a swim once a week and get her to climb the stairs 3-4 times a week, but her weight is still the same. The vet  has said that he's not sure how to get her to lose
it other than to continue as I have been but I'm worried it may effect her health if I cant get her to lose any. Do you have any suggestions?

Thanks for your help.
Sharlene

Answer
Hello Sharlene from from the UK. I do have a suggestion. Now, take my advice with a grain of salt as there are as many methods and ways to feed snakes as there are opinions in the world. What keeps my collection on par is feeding the only once per month, an adequate sized meal. This is less than conventional wisdom. Most say to feed every week or two, but my 20 snakes from cobras to king snakes have been doing just fine for 10 years on monthly feedings. My suggestion is to feed them 1 appropriately sized rat once per month and keep up the exercise.