Is there such a thing as a healthy diet? Are diets by definition healthy?
Perhaps surprisingly, the answer tends to be in the negative. Many diets are attention-grabbing attempts to cash in on people's desire for weight loss, offering false promises or short-term gains that are almost impossible to maintain.
Other claim to be a healthy diet yet have almost no long-term effect and it's a wonder they ever caught on – cabbage soup diet anyone?
And many others might take you down that dress or belt size in time for holiday but is starving your body of energy really a recipe for long term health?
To be truly healthy a diet has to be a plan for life where the aim is for improved health, as well as weight loss.
Weight loss might be the initial motivation for starting a diet but that is actually only a bi-product of the overall health benefits a good diet can provide.
A diet can help weight stay off but can also help with symptoms of various health conditions, such as diabetes, PCOS, epilepsy and depression.
A healthy diet is also one which anyone could benefit from, not just a few who have a specific weight issue.
Different diets may use different strategies of reducing energy intake. Whether it’s reducing fat intake, total calories or carbohydrates. Or even specific recommendations, such as reducing portion size.
Healthy diets work within a diet plan: a framework that states how to stay on the diet and then how to maintain the healthy lifestyle once the initial phase is over.
The early diets were, shall we say, experimental. William the Conqueror even cut out everything bar alcohol in a bid to lose weight; like many diets it is said to have worked in the short term. The longer term wasn't so good.
The vast majority of more modern diets work on the basic premise that cut calories and you'll reduce body weight.
The aim is to leave the body hungry so you create a caloric deficient; your body burns up excess bodyfat and you become leaner.
And the basic premise works. If you cut calories enough you will lose weight, but is it maintainable and is it healthy?
Creating a calorie deficit leaves you hungry so any dieter will have to cope with regular hunger pangs. Most people find this difficult in the long-term so studies show that a year, six months even, after low calorie diets, most people regain the weight.
In addition to this, there is the psychological and emotional damage of seeing all the hard work count for nothing.
Most diets are competing along similar lines. Sadly not competing to make people healthier but competing to gain attention, their weight loss is the fastest, their plan the easiest to follow.
One of the latest is the 5:2, eat what you want for five days and eat around 500 calories for the other two days of the week. Are things that simple usually effective?
Truly healthy diets start from a different motivation, not for profit but to help with a need that affects millions.
Diets that are serious will also take a more scientific approach, opening themselves up to peer-reviewed analysis.
After initial weight loss, a large part of a diet being healthy is also whether weight loss can be maintained for the long term.
No serious diet should simply say 'you've lost the weight, now you're on your own' yet many do.
Atkins counters this and should be viewed as a ‘lifestyle change’ rather than a short term ‘fad’ diet. After the initial phase of reducing carbs, except vegetables, other carbs are re-introduced until weight stabilises. This makes it easier to find the amount of carbs you, as an individual, needs to maintain weight loss.
And that's all you can ask of any diet – are the aims realistic and is it a plan for the long term. The few that meet these criteria are the healthy -or healthier- diets.