It's not a good idea to be either underweight or overweight. Eating too much can make you overweight, which can lead to ill health, such as heart disease, high blood pressure or diabetes. Not eating as much food as your body needs could also affect your health. If you're concerned about your weight, get in touch with your GP or a dietitian. But if you just need to lose a little weight and you want some help to get you started, have a look at the practical tips and advice in this section.