Meanwhile, aerobic exercise such as walking, as well as strength training, can ease symptoms and improve quality of life.
Starting exercise programmes may initially make the pain worse, but this should settle down, the guidance suggests.
It also gives recommendations on the use of medicines, such as offering non-steroidal anti-inflammatory drugs (NSAIDs) but not offering paracetamol, glucosamine or strong opioids.
Nice said there was a risk of addiction with strong opioids, while new evidence suggests little or no benefit for some medicines when it comes to quality of life and pain levels.
In the guidance, doctors are told to diagnose osteoarthritis – the most common form of arthritis – themselves without further investigation in people aged 45 or over who have activity-related joint pain.
Patients should also have no morning joint-related stiffness, or morning stiffness that lasts no longer than 30 minutes to be diagnosed this way.
The draft guideline says people can be offered tailored exercise programmes, with an explanation that “doing regular and consistent exercise, even though this may initially cause discomfort, will be beneficial for their joints”.
Exercising in the long-term also increases its benefits, the guideline adds.
When it comes to weight loss, people will be told that “any amount of weight loss is likely to be beneficial, but losing 10% of their body weight is likely to be better than 5%.”
Dr Paul Chrisp, director for the centre for guidelines at Nice, said: “Osteoarthritis can cause people discomfort and prevent them from undertaking some of their normal daily activities.
“However, there is evidence which shows muscle strengthening and aerobic exercise can have an impact on not just managing the condition, but also providing people with an improved quality of life.
“Beginning that journey can be uncomfortable for some people at first, and they should be supported and provided with enough information to help them to manage their condition over a long period of time.