No-one chooses to be obese (defined as having a BMI of 30 or above). People can be cruelly judgemental about your weight, it can shatter your self-confidence and physically it puts you at risk of chronic conditions like cardiovascular disease and type 2 diabetes. As if those challenges weren’t enough to contend with, another common condition associated with obesity is knee pain.
In short, carrying excess body weight puts increased stress on your knees. Not only can this make one or both become swollen and sensitive it can also increase your chances of developing osteoarthritis or OA (the most common type of arthritis caused when joint-cushioning cartilage wears away). OA tends to develop gradually but can get noticeably worse as time goes on, with some people reporting an unpleasant sensation of bone grating against bone.1 Research from the US shows overweight women are four times more likely to develop OA than those of a healthier weight. The good news is that, for every 11lb weight lost, that risk is reduced by half.2
Conditions or diseases that cause knee pain
Other conditions or diseases that can cause knee pain and which are exacerbated by being very overweight include:
Gout: a type of arthritis caused by the build-up of uric acid which causes sudden, sometimes excruciating joint pain most commonly affecting the big toe but sometimes other joints such as the knee. Pain typically flares up in the middle of the night and an episode can last for a couple of days to a couple of weeks. Eating too much red meat and drinking too much alcohol are known risk factors.3
- Tendonitis: inflammation of tendons can cause pain between the kneecap and shin, with swelling and inflammation. While this often results from a sports injury, it is not helped by putting extra pressure on the tendons if you are carrying extra weight. The pain typically feels worse when you move, particularly walking uphill or up stairs.4
- Bursitis: inflammation of fluid-filled sacs (bursae) that help to cushion the joints and keep tissues from rubbing against bone is caused by repetitive motion or injury but is aggravated by being overweight. The resulting pain tends to be dull and achy and increases when you move or press on the tender area. In severe cases, you may develop a large, fluctuant lump, and have difficulty bending the knee. 5
- Rheumatoid arthritis: an inflammatory autoimmune condition where the immune system attacks healthy joint tissue (synovial lining). It typically causes throbbing pain and stiffness in the joints which is characteristically worse in the mornings or after a period of inactivity.6
Some of these conditions will eventually clear up on their own but all are significantly improved by losing weight.
Inflammation and joint pain
Overeating increases inflammation in the body.7 The more weight you are carrying, the more fat cells you have which release a type of protein-based immune substances (cytokines) which accumulate to cause inflammation. This inflammatory process is implicated in almost all chronic conditions, including arthritis. Unfortunately, getting little or no exercise and having a high calorie diet containing too much sugar, processed or fast food and ‘bad’ fats – appears to promote inflammation, partly through effects on the liver.
Foods known to trigger the release of cytokines include sugar (in biscuits, pastries, sweets, breakfast cereals), saturated fats (found in cheese, crisps, processed meat products, red meat), trans fats (in fast food, processed food, biscuits, pastries and some margarines) and refined carbohydrates (white bread, white rice, potatoes, chips). Switching to a diet containing known anti-inflammatory foods like oily fish, nuts, seeds, pulses and olive oil and plenty of antioxidant rich fruit and vegetables will help, which is why following a typical Mediterranean diet can reduce symptoms of inflammatory conditions.
Some spices including turmeric and ginger also have a protective effect against inflammation. Lose weight and you lower the amount of inflammatory chemicals produced in the body. Shedding around 10 per cent of your body weight has been shown in studies to help reverse this inflammatory effect.8
How to lose weight
There is no single, tried and tested, guaranteed way of losing weight. From calorie-controlled meal replacements, to commercial diet groups like Weight Watchers and Slimming World, or more recent diet trends like intermittent fasting or high protein, low carbohydrate Keto diets, all appear to help some people achieve modest and sometimes long-term weight loss.
Recent research suggests the diet itself appears to make less difference to success, than how well you can stick with your chosen plan.9 So, if you love carbs you are unlikely to get on with a Keto or Atkins style plan. And if you start to feel shaky if you don’t eat regularly you’re unlikely to thrive on an intermittent fasting plan. You need something that is going to fit into your lifestyle with relative ease and is not too restrictive. Something like the free NHS Weight Loss Guide, a 12-week diet and exercise plan encourages you to lose an achievable 1lb-2lbs a week. 10 If you have a lot of weight to lose this can sound painfully slow and daunting but it is more sustainable. And think of the payback: a 2005 study of overweight and obese adults with OA of the knee found losing just 1lb in weight resulted in 4lbs of pressure being removed from the knee. This means if you can shed 10lbs, you could take a staggering 40lbs worth of pressure off your knees.11
Building up weight loss
Whatever weight loss plan you choose they are all basically a variation on the theme of burning more calories than you consume. Add exercise to the equation and you should not only help to burn fat faster you will also help build muscle and to alleviate the pain and stiffness associated with knee pain. It might feel like the last thing you want to be doing if your knees are hurting and you find it difficult to move around but, whatever the size of your waistline, exercise will benefit your health – physically and mentally. Start with an activity that is low impact and easy to perform like walking or exercising in water (the water helps cushion your joints and knees and provides support to reduce pressure on joints). Begin slowly, with a few minutes of walking or other exercise daily and gradually build up to three, 10-minute bursts a day.
Taking the stress off
Ultimately, keeping your weight down, eating a balanced diet and exercising should go a long way to keeping you and your knees healthy but this should form part of a balanced lifestyle generally. If you feel you aren’t getting the full complement of daily nutrients from your diet, because of cutting back on food to lose weight, you might benefit from a multivitamin. There are also a range of supplements shown to help support joint health including fish oils, glucosamine and rosehip extract. Drink plenty of water too, a glass before every main meal is an effective weight loss trick12 plus it can also stop you from becoming dehydrated which can contribute to joint pain. Get enough sleep: research links lack of sleep to obesity and a study has shown those who slept for around eight hours nightly were more likely to successfully lose weight. The same study also found those with lower stress levels were also more likely to shed weight.13 Exercising should help you deal better with stress as well as ensuring you sleep better. Look after yourself, lose weight slowly and change your habits little by little. It takes time and determination, but the rewards are ultimately worth it.14
If you’re interested in learning more about how to keep your joints healthy, head over to our advice centre for more information.