If you're trying to stay in shape or maintain a healthy weight, it can be hard to tell which tricks are working for your body and which aren't.

Sure, you battled your chocolate cravings at 11am but then you ended up eating twice as much dessert as usual after dinner. Sometimes, it's better to relax your attitude to food and fitness and just do what feels right.

Here are some health rules it's okay to break every once in a while…

1. No junk food, ever
Denying yourself when you have cravings can often backfire later in the day when you overindulge without thinking. If you have a craving for something sweet or unhealthy and it doesn't pass, don't just block it out! It's better to eat something unhealthy and enjoy it in the moment, rather than overeating later and feeling guilty for it.

2. Only eat salads
Yes, plain salads are a great option if you're trying to eat lightly, but they lack the comfort of heartier foods. Why not swap that boring lettuce for a non-creamy soup, some grilled veg or a wholewheat sandwich? You'll feel fuller and more satisfied without harming your weight loss plan. Adding cooked grains or beans to a salad can also help to make it more appealing, without adding fat or sugar.

3. Exercise every day
Your body needs time to rest! If you're lacking in sleep, allow yourself a lie-in and skip that morning spin class. In the long run it'll be better for your health and fitness levels.

4. Control your portions
"Portion control" seems to be the word of the year for anyone with an interest in clean eating and fitness. But certain non-starchy foods like salad leaves, peppers, celery and cucumber do not need to be strictly controlled. If you find you're getting sick of tiny dinners or feeling unsatisfied, try adding extra amounts of these safe foods to your plate.

5. No eating after 6pm
Your body doesn't automatically store calories as fat if they're consumed at night. If you've stayed late at work or are starving after an evening workout, give your body the fuel it needs. Skipping meals for the sake of not eating after dark will just slow down your metabolism in the long run. Try to keep evening meals healthy – but don't deprive yourself of food!

6. No bread
Yes, white bread is a refined carb that is generally high in calories. But wholegrain breads are packed with fibre and will leave you feeling full without bloating. Carbohydrates are your body's preferred source of energy, so give in to your needs!

7. No fatty foods
Fried and greasy foods should generally be avoided if you're dieting – but their high fat content isn't the only reason they're bad. Certain foods contain high levels of healthy fats which your body actually needs to help absorb nutrients. Nuts, seeds, olive oil and avocado might be high in fat on paper, but they're better than a snack box from the chipper any day!