Why you shouldn’t lose weight too quickly for Christmas

With the festive party season nearing upon us again, many of us will be worrying about waistlines.

With just over six weeks until Christmas, it’s tempting to embark on a mission to drop a dress size or two.

Indeed, this is the time when you can’t open a women’s magazine without being bombarded by the latest quick-fix diet.  

But leading Harley Street nutritionist Rhiannon Lambert is urging people to resist crash diets – because they can make you fatter and cause a host of other health problems.

Crash diets typically involve severely cutting back on calories, leaving only 1,000 or even 500 calories per day. 

Often they are paired with other ‘quick fixes’ like juice cleanses, diuretics or diet pills.

Here are four reasons why losing weight too quickly isn’t a good idea.

1. You’ll lose water weight

The reason people will put weight back on after going on a crash diet is because what they’ve lost isn’t really fat at all – it’s water weight.

‘Through these diets, fast weight loss can happen and usually more than two pounds can be lost in the first week,’ Rhiannon told  The Independent. 

‘However, a lot of this “lost weight” is actually water weight, which is due to the glycogen that is burnt for energy as the restricted diet is not bringing in enough energy for the body, so it has to use its stores.’ 

2. Nutritional deficiencies 

Low calorie diets tend to be very restrictive, bringing the risk that your body will not be able to get the key nutrients it needs. 

‘Along with the nutritional deficiency comes the effects of the deficiency. For example, a lack of Vitamin D, calcium and phosphorus can lead to weak and brittle bones,’ said Rhiannon.

‘Additionally, fatigue and anaemia can arise due to minimal iron and Vitamin B12 in the diet.’ 

In addition, low calorie diets can lead to a deficiency in sodium and potassium. These electrolytes are used in nerve and muscle function, and play an important role in regulating the beating of the heart.

A lack of these nutrients can lead to increased risk of heart attack.

Harley Street nutritionist Rhiannon Lambert is urging people not to get tempted to follow a crash diet to get in shape for Christmas

2. You’ll lose muscle – and slow your metabolism

Researchers at Maastricht University in the Netherlands put 25 people into two groups.

The first group embarked on a five-week diet consisting of just 500 calories a day. The second group also went on a diet, but theirs was spread over a longer period of 12 weeks and they were allowed 1,250 calories per day. 

At the end of both diets, participants in both groups lost the same – an average of 19 lost pounds.

However, the 500-calorie plan dieters lost 3.5 pounds of muscle mass, while the 1,250-calorie group lost only 1.3 pounds of muscle. 

In other words, among the very -low-calorie dieters, 18 per cent of their weight loss was attributed to muscle loss, while only 7.7 percent of the other group’s weight loss was muscle.

It’s important to preserving muscle mass because it boosts your resting metabolism – and that makes your body burn more calories.

4. You’ll likely regain everything you lost

We’ve already explained how water weight explains why the scales will likely jump back up again as soon as you start eating normally again.

Willpower is another factor. Yo-yo dieting — or weight cycling, as experts call it — is practically a national pastime. 

Crash diets are so hard to stick to that people tend to lose their willpower and end up regaining any weight lost, US researchers reported in the journal Obesity in August.

Having monitored the outcome of 183 dieters over two years, the scientists at Drexel University, Philadelphia, who were behind the study, concluded that it’s the slowly but surely approach, losing a pound a week, that brings the greatest results.

And to achieve that, it seems that making mini tweaks, rather than major alterations, to your diet brings the greatest success.   

The best approach to weight loss   

According to the NHS, a healthy amount of weight to lose per week is one to two pounds.

It’s something we all know but need a reminder of – slow and steady fat loss is key to keeping the weight off long-term, says Rhiannon whose book Re-Nourish: A Simple Way To Eat Well is out next month.

Some experts advise ditching the scales when you are trying to lose weight (stock photo)

When done gradually, you’re more likely to make permanent lifestyle changes, which will include developing a healthier relationship with food and skills for mindful eating, she said. 

‘Increase fruit and vegetable intake, complex carbohydrates instead of simple carbohydrates, and decrease processed sugary foods,’ suggests Rhiannon.    

And remember, if you’re working out and doing a lot of strength-training exercise, you may not see the number on the scales drop.

You may still be burning fat because you’re building muscle at the same time – and muscle weighs more than fat.

Some experts – including The Body Coach – advise ditching the scales entirely, and focusing on how your clothes fit or taking progress photos.