One of the least talked about side effects after gastric sleeve surgery is how cold you can feel once the weight starts coming off. Before surgery, both of us ran warm – sometimes too warm. Now, over two years post-op, we practically live under heated blankets. And we’re not exaggerating.
We have heated blankets in the living room, heated blankets in the bedroom, and heated throws draped over every sofa. James wears a heated gilet to work all year round – yes, including summer. If it drops below 18°C, he’s shivering. If you’re experiencing the same thing, you’re not alone, and there are straightforward reasons for it.
Why cold intolerance happens after sleeve surgery
Loss of insulation. Body fat acts as natural thermal insulation. When you lose a significant amount – as both of us did – your body has less padding to retain heat. The effect is immediately noticeable and catches most people off guard.
Reduced calorie intake. Your body generates heat as a byproduct of metabolic processes. When you’re eating a fraction of what you used to, particularly in the first year post-op, your body produces less internal heat as a direct consequence. This is most pronounced in the rapid weight loss phase and typically improves as intake gradually increases.
Hormonal changes. Significant weight loss affects hormones involved in metabolism and temperature regulation, including thyroid hormones. These generally stabilise over time as weight loss slows, but the adjustment period can span many months.
Reduced peripheral circulation. As body composition changes, the way your body distributes heat changes with it. Many people find their hands, feet, and nose become disproportionately cold – the extremities suffer first when your body’s thermal regulation is under strain.
Nutritional deficiencies. This one is important and often overlooked. Iron deficiency anaemia causes cold intolerance – it’s one of the classic symptoms. James experienced significant cold sensitivity as part of his month-11 deficiency crisis, alongside fatigue and brain fog. Once iron and B12 levels were corrected, the cold intolerance noticeably improved. If you’re cold all the time, it’s worth asking your GP to check your iron, ferritin, and thyroid function alongside your other bariatric bloods – not just assuming it’s the weight loss.
How we cope
Heated blankets. Genuinely life-changing. We didn’t think we’d become “heated blanket people” but here we are. A heated throw on the sofa and a heated underblanket on the bed make a real difference to quality of life in the colder months. They’re also much cheaper to run than heating an entire room.
James’s heated gilet. This is his single most useful post-op purchase. It has adjustable heat zones and keeps core temperature up without heavy layering. He wears it to work, in the car, and at home. Yes, in summer. It’s become a fixture.
Warm drinks. Hot tea, warm squash, or simply warm water throughout the day help maintain internal temperature and double as hydration. Kirsten finds this particularly helpful in the morning before her body has fully warmed up for the day.
Layers. We carry hoodies everywhere now. A lighter body loses heat faster; layering traps it more effectively. Thin thermal base layers worn under normal clothes make a significant difference in cold weather without adding bulk.
Movement. Even light activity – a short walk, tidying up, gentle stretching – generates body heat quickly. Sitting still when already cold makes it worse. This is probably the most underrated strategy because it costs nothing and works immediately.
Does it improve?
For most people, cold intolerance improves as weight stabilises, calorie intake gradually increases, and hormone levels settle. For us, two years on, we still run colder than we did pre-surgery but nowhere near as extreme as those first six to twelve months. The heated gilet remains non-negotiable for James, but the days of being genuinely unable to get warm indoors are mostly behind us.
If cold intolerance is severe, persistent, or accompanied by other symptoms like significant fatigue, hair loss, or poor concentration, ask your GP to check your thyroid function and iron levels. These are treatable and addressing them makes a real difference – as we found out at month 11.
Sources cited in this post: NHS – Feeling cold: causes and when to see a GP
BOMSS – Guidelines on perioperative and postoperative biochemical monitoring and micronutrient replacement for bariatric patients
Parrott J et al. – ASMBS Integrated Health Nutritional Guidelines for the Surgical Weight Loss Patient 2016 Update (Surgery for Obesity and Related Diseases, 2017)
NHS – Iron deficiency anaemia
- NHS, “Weight loss surgery”: https://www.nhs.uk/conditions/weight-loss-surgery/
- British Obesity & Metabolic Surgery Society (BOMSS): https://bomss.org/
About this content
This blog is written by James and Kirsten, a couple from the UK who had gastric sleeve surgery together in March 2024.
We started this blog because we couldn't find any sources of content that details before surgery, the surgery and then life post surgery - so we decided to write one ourselves.
Everything on this site is based on our own experience and the research we have done along the way. It is not medical advice. Gastric sleeve surgery is a serious procedure and every patient's journey is different. Please always consult your own bariatric team or GP before making any decisions about your health or treatment.
Some posts on this site may contain featured or sponsored content, or affiliate links. Where this is the case, it will always be clearly stated at the top of the article. Our opinions are always our own.
Publish Date: 12 November 2025 | Last Reviewed: 27 June 2026 | Next Planned Review: 27 December 2027