NUH’s healthy keto diet leads to weight loss without increasing bad cholesterol levels

SINGAPORE – Weighing 115kg and standing at 1.74m, Mr Tan Ban Thong had trouble buying clothes. Walking a short distance left him breathless and flying was tough as airplane seats were often not wide enough.

The 60-year-old deputy director of human resources is in a much better place today after he shed 25kg last year.

The breathlessness has gone away, and he has better control of his health issues, including diabetes, hypertension and non-alcoholic fatty liver disease.

The secret to his success is the Healthy Ketogenic diet developed by Dr Lim Su Lin, the chief dietitian at the National University Hospital (NUH).

The key feature of the diet is keeping to a net carbohydrate level (carbohydrates minus fiber) of 50g or less a day to induce ketosis, where stored fat (instead of glucose) is broken down to provide energy.

That works out to three or 3½ slices of white bread, or 1¼ cup of rice a day.

“In many weight loss diets, people usually (give up) because of hunger pangs,” said Dr Lim, at an event to share the findings of a study on the diet at NUH on Wednesday.

With a healthy keto diet, however, once a person reaches ketosis in typically two to three days, the gut will naturally produce higher levels of glucagon-like peptide-1 (GLP-1), a hormone that helps to increase satiety and reduce cravings , she added.

It is different from traditional keto diets, where one may eat a high amount of saturated fats and red meats in place of carbohydrates. Such diets have been linked to increased levels of low-density lipoproteins (LDL), or bad cholesterol.

This keto diet emphasizes healthy fats, such as those found in nuts, seeds, fatty fish and unsaturated oils, as well as lean protein, high fiber from non-starchy vegetables and low-carb fruit. Fat consumption is kept at less than 50 per cent of total daily energy, unlike a traditional keto diet, in which fat can account for up to 90 per cent of total daily energy. The healthy keto diet also restricts calories according to the person’s profile.

Dr Lim said that participants on the diet in an ongoing clinical trial showed no increased level of LDL at the six-month, as well as the one-year mark.

The trial involved 80 participants who were National University Health System staff, like Mr Tan. They all have a body mass index – a measure that uses height and weight to work out if one is at a healthy weight – of more than 27.5.

The group assigned the healthy keto diet lost an average of 7.4 kg over six months, while another group assigned a standard low-fat, calorie-restricted weight-loss diet lost an average of 4.2kg. They used the NUH’s nBuddy keto mobile app to help them select their food.

At six months, all participants with diabetes or pre-diabetes managed to reduce their blood glucose levels, while 70 per cent of those with high blood pressure saw it improve. Those who follow the healthy keto diet closely also find a reduced dependence on their prescribed medications and overall, a better quality of life.