Shaking up weight loss: What to know about meal replacements

What are the pros and cons of meal replacements, like protein shakes, if you want to shed some extra kilos?

If you’ve gained weight and are struggling to shift it, you may be looking to meal replacements to help stop the spread.

And new British research suggests a diet based on meal replacements – like protein shakes, soups or bars – may help in the short term.

An Oxford University study found people who replaced daily meals with shakes and bars lost an average 10.7kg over 12 months, and this weight loss also helped reduce their risk of developing heart disease, stroke and diabetes.

For the first eight weeks, the group of clinically obese or “substantially overweight” consumed protein-rich shakes, bars and soups along with milk, water and fibre supplements.

Their daily kilojoule intake was around 3389kJ, around half the normal amount for adults.

After eight weeks, food was gradually reintroduced along with one meal replacement product a day.

meal replacements

So how do meal replacements work?

Very low-calorie meal replacements are designed to give our body the nutrients it needs in fewer kilojoules.

Most contain few carbohydrates, have added vitamins and minerals and are protein-based.

When we consume fewer kilojoules than we burn, fuel stored in our muscles and liver – called glycogen – runs low and our body starts burning fat.

Burning fat generates ketones and these supress hunger, which helps people stick with their diet.

Professor John Dixon, head of clinical obesity research at the Baker Institute, says very low-calorie meal replacements can be a safe way to help kickstart and sustain weight loss in people with a BMI of 27 or more.

“People don’t become nutrient deficient and very low-calorie diets don’t cause excessive loss of muscle and bone,” he says.

“They take a lot of weight off quite quickly and so they also provide an incentive.”

Partial meal replacement diets can help keep weight off once it is shed, too.

meal replacements

What to know about using meal replacements

Be prepared to be hungry for the first three to four days – that’s usually the time when people give up, says Prof Dixon.

“But after that you lose your hunger substantially when burning fat and can stay on the diet with relative ease,” he says.

“They suppress appetite and so a small calorie intake becomes sufficient.”

How long can use meal replacements?

“These diets enable people to lose weight and to keep off substantial amounts of weight for years,” says Prof Dixon.

“They are very valuable.

“If you lose weight and notice it creeping up again, you can return to a meal replacement program or to a partial meal replacement program.

Prof Dixon says although meal replacements are readily available to buy, it’s best to speak to a health professional before starting such a diet.

Written by Sarah Marinos.