• How healthy is it to cut carbohydrate-rich foods from your diet for the purpose of weight loss? (E+/Getty Images)Source: E+/Getty Images
An honest look at the pros and cons of cutting carbs from your diet, including potential short-term weight loss and long-term kidney damage.
Yasmin Noone

13 Mar 2019 - 10:25 AM  UPDATED 21 Mar 2019 - 5:01 PM

In the rush to shed kilos and battle sizeable waistlines, a stream of high protein, low carbohydrate diets have become so Insta-famous that their household names have become synonymous with weight loss success.

There’s the Atkins Diet, Keto Diet, Paleo diet and a host of other low carb, high protein eating plans – tried and tested by influential celebrities like Kim Kardashian and Halle Berry – that all recommend cutting or restricting the amount of carbohydrates you consume each day to lose weight.

Obesity is a major health issue for Australia. But how healthy is it to cut the important complex carbohydrates found in foods like bread, cereals, pasta, rice and starchy vegetables from your diet for no other purpose but weight loss? 

When can a low carb diet help you?

The body governing World Kidney Day states that there’s some international evidence that a low carbohydrate diet (LCD) may benefit your kidney function if you’re obese.

One of these studies was conducted in Japan in 2016 and published in the British Journal of Nutrition. Kyoto researchers analysed a series of randomised control trials involving over 1,600 overweight and obese people with normal kidney function following a LCD.

The results showed that a LCD slightly improved participants’ renal function. This could be because being overweight or obese increases your risk of developing diabetes or high blood pressure, which are both causes of kidney disease.

...there’s some international evidence that a low carbohydrate diet (LCD) may benefit your kidney function if you’re obese.

According to Harvard T.H Chan School of Public Health’s dietary advice on the Keto diet, there’s also growing interest in researching the use of low carb diets to better manage type 2 diabetes.

However, the scientific jury is still out on the impact of a LCD on your overall health over time as there have not been enough human studies conducted to recommend it for diabetes or weight loss.

The massive downside to a LCD is the fact that people usually compensate the carb cuts by increasing the amount of protein they consume. Yet various studies also warn that consuming a diet high in protein may cause long-term kidney damage in specific at-risk groups.

If you follow a low-carb, high-fat diet, it may hurt your gut: study
A low-carb, high-fat diet may be great to help you lose weight. But, according to a new international study, this diet could damage your good gut bacteria and may cause inflammation throughout your body in the long term.

How are carbs, protein and your kidneys related?

A low carb diet may achieve weight loss by forcing the body to burn fat stores through a process called ketosis.

“If you don't eat enough carbs to make energy, your body will turn to its fat and protein stores (including your muscles) to make energy instead,” explains Vincent Candrawinata, a Doctor of Clinical Nutrition from Renovatio.

"Once your body begins to burn large amounts of body fat, compounds called ketones are accumulated in the body,” says Dr Candrawinata.

He warns that over a long period of time, high levels of ketones could cause your body to burn protein in the tissues of your organs for energy, such as your kidneys. “This may cause damage to organs, which can lead to organ failure.”

Aboriginal and Torres Strait Islanders  are also more than twice as likely as non-Indigenous people to have indicators of chronic kidney disease.

People with existing kidney issues or those in a high-risk group of kidney disease may face a greater risk of kidney damage if they go on a LCD, high protein diet over a long period of time. This includes individuals from cultural groups with a genetic predisposition to kidney disease such as Aboriginal and Torres Strait Islander peoples.

Kidney Health Australia estimates that one-in-every 10 adults nationwide have signs of chronic kidney disease. However, almost one-in-five Aboriginal and Torres Strait Islander people aged over 18 had indicators of chronic kidney disease. Aboriginal and Torres Strait Islanders are also more than twice as likely as non-Indigenous people to have indicators of chronic kidney disease.

Other at-risk groups include people with diabetes, high blood pressure and smokers.

These are the carbs you should eat to help with your diet
Not all carbohydrates are created equal. Dietitians recommend that we should eat a very specific type of carb to manage our weight and prevent chronic disease: whole grains.

"A high protein diet may worsen kidney function in people with existing kidney issues or at high risk of kidney issues because your body may have trouble eliminating all the waste products of protein metabolism,” he says. 

“Some high protein diets restrict carbohydrate intake so much they can also result in nutritional deficiencies or an insufficient fibre intake, which can cause problems such as bad breath, headaches and constipation.”

“The end goal of a diet or lifestyle change should always be to be healthy and not just to lose weight.”

The health consequences of a long-term LCD, high protein diet sound extreme but the long-term risks for various individuals are real.

"A more permanent solution for weight loss than a high protein, LCD diet is to change your lifestyle, to eat lower fat, high fibre foods including plenty of fruits and vegetables; unprocessed grains and cereals, and legumes; fish, chicken and lean meats; and to exercise regularly.

“Such lifestyle changes will also result in weight loss, an improvement in overall health, and prevent degenerative diseases.

“The end goal of a diet or lifestyle change should always be to be healthy and not just to lose weight.”

Following the wrong kind of low-carb diet could make you die younger: study
"Animal-based low carbohydrate diets should be discouraged.”
You can lose weight by eating pasta, says new study
Finally, scientists give us the all clear to go on a diet where we're required to eat carby-pasta dishes to lose weight.
Which diet is better – low fat or low carb? The experts say neither
Forget debating the pros and cons of a low fat versus a carb-free diet if you want to lose weight. The experts say there’s no major difference, as long as you restrict your kilojoules.
What are ketogenic diets? Can they treat epilepsy and brain cancer?
A lot of claims are made about high-fat ketogenic diets. A lot are totally unproven. Here's what science really says.
Academic urges careful thinking on paleo for diabetes
After reviewing existing studies, a university researcher has urged caution about claims regarding the paleo diet and diabetes.