A dramatic lifestyle change for one half of a couple can place the relationship under huge strain. Let's face it: if you suddenly start turning down wine in favour of carrot juice and getting up at 6.30am to jog round the park, it may take a while for your partner to adjust. A recent US study found that non-dieters often try to sabotage their partners' efforts - and admit to feeling threatened and insecure when a significant other loses weight. The solution? Agree to make changes together. 'When both partners bought into the idea of healthy changes and were supportive of one another, weight loss appeared to bring people closer,' says Dr Lynsey Romo, who led the study at North Carolina State University.

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Feel-good diets for autumn & winter
Stop the empty calories!  - foods to avoid when dieting
Want to lose weight? Read all our top diet plans

The best way to lose weight involves a combination of healthy eating and regular exercise. Forget about the latter and you might shift those pounds in the short-term, but the results are unlikely to last. 'Exercise is the key to establishing long-term weight loss gains,' says Dave Kyle, head trainer for Les Mills. 'By exercising, you increase the body's ability to burn off calories more efficiently, so there's less chance that you will retain or regain weight. Over time, exercise also suppresses our appetite for junk foods. The body tends to tell you what it needs: fewer fast-release sugary foods and more protein and slow-release carbohydrates.'

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Feel-good diets for autumn & winter
Stop the empty calories!  - foods to avoid when dieting
Want to lose weight? Read all our top diet plans

Lose too much weight too quickly and you can end up looking tired and gaunt: rosy cheeks are replaced with sunken cheekbones and once-bright eyes turn into big black circles. The reason? 'Aggressive weight loss can result in fat loss from your face, which is very difficult to coax back,' explains beauty coach Antonia Mariconda of The Cosmedic Coach. 'Facial fat actually makes us look youthful. When this disappears after a dramatic drop in weight, people can end up looking haggard and old. To avoid it happening, weight loss should be done gradually and sensibly over a long-term period - one step at a time.'

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Feel-good diets for autumn & winter
Stop the empty calories!  - foods to avoid when dieting
Want to lose weight? Read all our top diet plans

Yes, you can lose weight by cutting calories. But cut out the wrong calories and you could be jeopardising your long-term health. 'In order to reduce the risk of heart disease later in life, we need to be eating a balanced diet that's low in sodium and saturated fats,' says Dave Kyle. 'If you cut out the wrong nutrients, it can lead to a build-up of toxins that will prevent the body from working efficiently.' Remember, simply being on a diet doesn't necessarily mean that you're eating healthily; sometimes, it can mean quite the opposite.

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Feel-good diets for autumn & winter
Stop the empty calories!  - foods to avoid when dieting
Want to lose weight? Read all our top diet plans

Are you a serial dieter? Do you embrace fad diet after fad diet, then pile the pounds back on again in between? Two words of advice: stop it! Nutritional therapist Elena Lucchi from Borecole Nutrition, explains why: 'Crash diets, which involve very restricted calorie intakes, usually result in rapid weight loss. However, that loss is mainly muscle and water. These diets are neither healthy nor sustainable - and when stopped, the rebound weight gain is usually comprised of fat. This is bad news for our metabolism because people with more muscle burn more calories, even when they're resting. Crash-diet regularly and your metabolic rate will eventually go down, which makes weight loss even more difficult.'

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Feel-good diets for autumn & winter
Stop the empty calories!  - foods to avoid when dieting
Want to lose weight? Read all our top diet plans

We're sticking with the fad diet theme here to explain exactly why shifting a lot of weight in a short space of time isn't the fantastic result you may initially think it is. So you lost nearly a stone in a week and can now squeeze into your little black dress? Now, try keeping that weight off. Not so easy, is it? Nutritionist Dr Carrie Rushton from the Health Supplements Information Service explains: 'A balanced, low-calorie diet of roughly 1,000 to 1,500 calories each day will shift around 0.5-1kg (1-2lbs) of body weight each week. Any more than that indicates you're losing fluid and muscle mass, rather than fat.'

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Feel-good diets for autumn & winter
Stop the empty calories!  - foods to avoid when dieting
Want to lose weight? Read all our top diet plans

Cutting out a meal may seem like a guaranteed way to shift those excess pounds - but, trust us, that tactic is definitely going to backfire. 'This is a common dieting tactic, but it's unsustainable and often ineffective because people end up snacking on unhealthy foods later in the day,' says Dr Carrie Rushton. 'Because breakfast cereals are fortified, dieters who skip their morning meal miss out on vital vitamins and minerals. In fact, studies show that overweight people often have low blood levels of vitamins A and D, and lower antioxidant levels, so it's a good idea to take a multivitamin supplement when dieting to safeguard your nutrient intakes.'

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Feel-good diets for autumn & winter
Stop the empty calories!  - foods to avoid when dieting
Want to lose weight? Read all our top diet plans

Our relationship with food is a complex issue, and people choose to diet for a variety of different reasons - many of them emotional. 'Sometimes, dieting may provide a sense of structure or control when an individual is facing issues in other areas of her life,' says psychotherapist Sunita Pattani, of the The Feel Free Project. 'It's not always necessarily the case that people engage in dieting as a direct distraction, but rather they are trying to tackle a different underlying issue, to which they mistakenly think dieting is the answer.' Of course, it's a good idea to get fit and shape up - but don't allow yourself to fall into the trap of thinking everything in your life will be fine if you can just drop a dress size.

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Feel-good diets for autumn & winter
Stop the empty calories!  - foods to avoid when dieting
Want to lose weight? Read all our top diet plans

If you do tend to diet as a distraction from other problems, the repercussions can become serious over time. The warning signs? Sunita Pattani explains: 'Your thinking where food and eating is concerned is no longer balanced. The diet becomes your focus, while those underlying issues continue to play themselves out in the background. Socialising may become a problem as you worry about what you'll eat when you go out. Relationships can suffer.' Self-awareness, gentle self-talk and being aware of your triggers can all help you overcome emotional eating. But for more advice and support, it's important to speak to your GP or contact eating disorders organisation Beat.

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Feel-good diets for autumn & winter
Stop the empty calories!  - foods to avoid when dieting
Want to lose weight? Read all our top diet plans

We've already explained why fad diets are inadvisable and unsustainable. But if you want more proof, it's worth noting that two out of five dieters quit their new regime within seven days, according to a recent survey commissioned by Alpro. The trick is to be realistic from the outset. You only get one lunchtime, so there's no point adopting a plan that requires you to eat 10 small meals a day. And if you're obliged to spend a fortune on supplements and rare health foods, it'll soon burn a hole in your bank balance. 'Tailor your eating plan to suit your work lifestyle and budget,' advises Alpro dietician Kate Arthur. 'This will make it easier to follow and means it becomes a lifestyle change that you can sustain forever.'

You might also like…
Feel-good diets for autumn & winter
Stop the empty calories!  - foods to avoid when dieting
Want to lose weight? Read all our top diet plans