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Antibiotics and weight gain


Full Member
S: 14st6lb C: 14st2lb G: 10st7lb BMI: 31 Loss: 0st4lb(1.98%)
I've been on a course of antibiotics for a week now and at weigh -in on wed, i'd put on 1lb. I was surprised because I'd stayed on track all week, and power walked every day. I know exercise can make you withhold fluids but was wondering if antibiotics can as well.

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Former SW Target Member
S: 18st10lb C: 16st4.5lb G: 15st3lb BMI: 36.9 Loss: 2st5.5lb(12.79%)
I always put it down to how crappy the antibiotics make me feel lol when I am on them I feel sick and have even less of an appetite than normal. I always find it funny that I never feel ill with the frequent infections until they start me on yet more antibiotics. My first weigh in at slimming world I was on antibiotics for a UTI lost 1.5lb, 2nd and 3rd weeks lost 3.5lb and 4.5lb, 4th week was on antibiotics for another UTI and gained 0.5lb (funny really since all my jeans are falling down) I didn't really do anything much different each week. I am sure that there will be plenty more before the baby is born so will have to see if I gain/lose less those weeks. ((hugs)) hope you feel better soon. Hugs Crystal xx


Full Member
S: 14st6lb C: 14st2lb G: 10st7lb BMI: 31 Loss: 0st4lb(1.98%)
Awww, thanks for your reply crystal:)
I know it's funny how our bodies behave. I'm still on antis and (wishful thinking) will lose 7lb next week! lol!

Good luck with your pregnancy. Hopefully you won't get any more UTI's, they're not nice at all.



Former SW Target Member
S: 18st10lb C: 16st4.5lb G: 15st3lb BMI: 36.9 Loss: 2st5.5lb(12.79%)
cranberry squash or cranberry tablets help a lot and so does drinking loads (lime squash seems to help more than water) although you do spend the majority of your day in the toilet ;) good luck with your weight loss next week. Hugs Crystal xx
I was very ill last year and was on antibiotics for a while. It played havoc with weight loss and took a while to get them out of my system. They were necessary, but I hope never to have to take them again!!
I'm on antibiotics for an impacted wisdom tooth at the minute. (only for a wk thank goodness!)
I started them on weds morning but weighed myself this am and I've put 2lbs on!
Although I have eaten a doughnut and some ice cream, but to be fair that's all I've had as it hurts to eat.
Just to add I had a kidney infection a few years ago and was admitted to hosp for a week on an antibiotic drip.
I lost 10 lbs in one week.....best diet ever as I only weighed about 10st 7lb to begin with. Mainly because hospital food is disgusting though I think!


Full Member
S: 14st6.5lb G: 11st0lb
Interesting question. I am on antibiotics at the moment, I started them last Sunday and I'd put on 0.5 when I weighed in on Wednesday. I didn't think anything of it becasue I did go off plan Saturday evening at a hen night but I was really good the rest of the week so maybe the antibiotics may have effected my weight.


Target Member
S: 14st0lb C: 9st0lb G: 9st0lb BMI: 23 Loss: 5st0lb(35.71%)
My thoughts are that the actual antibiotic has no fat or sugar in it, even if it did it would only have a trace, so wouldn't affect weight
I would think that the illness being treated could influence, you could have a loss of appetite which puts your body into starvation mode which could see weight gain, increased fluid intake could increase weight, etc
I know beechams hot lemons and cough medicine has loads of sugar, so if these for example were also being taken then syns could start creeping up
You might be more lethargic so burning a lot less calories than you would on a normal day
So everybody its time to get healthy :)
You are right - antibiotics don't have calories. But they do play havoc with your body's immune system and metabolism. It can't be helped because fighting the infection is obviously more important.


bye bye baby tummy
S: 14st2lb C: 12st9lb G: 9st7lb BMI: 27.7 Loss: 1st7lb(10.61%)
Antibiotics actually can make you loose weight im afraid

My baby had huge weigh issues and she had a dose of anti biotics for an infected belly button and the hv said that anti biotics can stop people from gaining weight...

BUT i would think that if you feel pants you might not be plan 100% i would worry about feeling better and THEN worry about weight

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