After we hit 40, the number on the scale can start to creep up. Women gain, on average, a kilo each year in their 40s, 50s and 60s. That's because low oestrogen levels during menopause can alter the balance of leptin and ghrelin levels - the hormones responsible for managing hunger - and increase appetite. Thyroid issues, stress, sleep problems, and certain medications can also contribute to weight gain. But, getting older doesn’t mean you have to put up with unwanted kilos. Better yet, what if you could stop them in their tracks? Try these simple tips from the experts to avoid weight gain after 40.