Losing weight is tough, but it's nothing compared to keeping the weight off. I'm sure I'm not the only one who has worked hard to achieve my weight loss goal, then gleefully given away all my "fat clothes" - only to find myself buying a new wardrobe in the same size two years later.

Unfortunately, when it comes to weight loss, there is no quick fix. Sure, there are diet drinks and meal substitutes, and personal trainers ready to put you through boot camp - but research proves two things:

• the faster you lose weight, the faster you're likely to put it all back on again.
• the more artificial the diet, the more likely you are to put the weight back on again.

I know how it feels - when we're feeling fat, we don't want to be told that it's going to take two years to get thin. And honestly, there's nothing wrong with going on a fad diet for a couple of weeks, just to give yourself a boost and feel like you've got started. But after that, you need to switch back to a sensible, long-term plan - and there are two good reasons for that.

All adults have developed a lifestyle that is full of habits - what you eat and drink and when, and how much you exercise.

When you go on a diet, you typically eat less food and exercise more - but that's not your natural way of living, so chances are that when you finish your diet, you'll go right back to eating and moving the way you did before the diet. Especially if you didn't like the taste of the diet food, and didn't enjoy the exercise. Yes, you'll get the odd pang of guilt about what you "should" be eating and what you "should" be doing, but those pangs will fade with time - which is why people often seem to be maintaining their weight for several months after a diet, but then the pounds start creeping on.

The secret to losing weight and keeping it off is to avoid making drastic and unpleasant changes to your lifestyle. Instead, make small changes which will have a gradual and relatively painless effect. Because the changes are small, you'll become accustomed to them, and they will eventually become a natural part of your everyday lifestyle - replacing the old bad habits.

One small change won't have much effect on its own, but the cumulative effect of lots of small changes can be startling.

One fundamental change you must make, is to learn the art of slow eating. Today, many of us have lost the ability to recognise our "full signal", which is one of the key reasons we overeat. If that applies to you, you won't feel satisfied when you're dieting, and will go back to eating big portions again afterwards. Learn to eat slowly and recognise when you're full, and you'll never have to worry about portion control again!

Another important change is to get your sweet tooth under control. I cured mine using the Carbohydrate Addicts' Diet, but any low carb diet plan can work. I still like sweet things occasionally, but I rarely eat more than a handful of jelly beans a day - and I honestly don't feel deprived.

The third major string to your bow is exercise. The important thing is to find an exercise you enjoy, and can incorporate into your daily routine without making sacrifices. I love dancing, so it never feels like exercise. Some people love swimming (at least in the summer). But if you just don't like getting hot and sweaty in any shape or form, then the 10,000 Steps Program is for you. This program is about finding ways to increase your "incidental exercise" - moving around more during the day, not necessarily at a fast pace or for long distances. Every extra step burns more calories and once again, this small shift to a more active lifestyle is insignificant enough to be absorbed into your everyday habits.

Here, I'm not talking about a psychological condition where you subconsciously don't want to be thin for some reason - although that does exist. No, I'm talking about a sabotage that is outside your control, and it's another reason why it's best to lose weight slowly. It's the body's set point.

The set point theory says that our brains like things just the way they are. If you've been overweight for a long time, your brain has decided that's normal. If you suddenly start losing weight, it panics and thinks "famine!" and immediately starts shutting down all non-essential services. That translates to a lower metabolic rate, which means you need less fuel, which makes it harder to lose weight.

Most people know about this - but what they don't know is what happens after the diet is over. If you've lost weight quickly, the brain still thinks there's a problem. According to its historical information, you're now underweight. If there's another famine, you're in trouble! So now you and your brain have opposite goals - you'd like to stay slim, thank you very much, but your brain is anxiously trying to get you back up where it thinks you belong.

In order to keep the weight off, you either need to keep a vigilant eye on your weight and keep it steady for several months - or you need to trick your brain into accepting a new setpoint. You can do this by losing weight slowly, because that gives the brain time to adjust and decide the new weight is OK. So you can see, this is another powerful argument for gradual weight loss instead of drastic dieting.

Here are a few more painless changes you can make - not in habits, but in specific foods:

• Avoid diet drinks or foods containing Aspartame or Phenylalanine - even if it's not dangerous (see clip), it's been shown to make you hungry!
  
• Take calcium tablets with dinner. People who take calcium supplements have been shown to lose more weight than people who don't.
• Use light or skim milk instead of full cream milk or half-and-half.
• Don't buy anything labelled "low fat" without checking the ingredients. Many "low fat" foods have extra sugar or corn syrup added to make up for the lost fat, so you're worse off.
• Don't use artificial sweeteners in tea and coffee (especially Aspartame - it increases your appetite). Instead, try cutting down the sugar, half a teaspoon at a time - take as many days/weeks as you need to get used to it before you take the next step. This will help reduce your sweet tooth, too.

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All text copyright Marisa Wright. Cherry Coke photo from Jake Spurlock. Scales by Brymo. Junk food photo thanks to Permanently Scatterbrained.