No easy way to sustainable weight loss

IN most affluent societies, an increasing proportion of the population tends to be overweight or obese. Hence it is not surprising that weight loss has become a common desire for many, both for aesthetic and medical reasons. Before jumping onto the weight-loss bandwagon, understanding the latest American Heart Association guidelines, published November 2013 in the Circulation journal, provides a practical approach to the management of excessive weight gain.

Who needs to lose weight?

Many people who undergo weight-loss programmes do it primarily for aesthetic reasons rather than medical. From the medical viewpoint, which individuals can benefit from weight loss?

Most criteria for the definition of overweight or obese condition utilise the Body Mass Index (BMI) calculation. BMI can be calculated as an individual's weight in kilograms divided by the square of their height in metres. Current US definitions consider a BMI (kg/sq m) of 18.5 to less than 25 as normal weight, 25 to less than 30 as overweight, 30 to less than 35 as class 1 obese, 35 to less than 40 as class 2 obese and 40 and above as class 3 obese or extreme obesity. These definitions categorise individuals into different risk categories for heart disease and obesity-related conditions.

One of the important factors to consider before deciding whether the individual will benefit from weight-loss programmes is to determine whether there are pre-existing medical conditions. The overweight or obese individual has to be assessed for evidence of heart disease, diabetes, high cholesterol and high blood pressure. For those whose BMI is 25 to less than 35, a waist circumference measurement of more than 88cm for women and more than 102cm for men indicates an increased risk of heart and metabolic disease. Obese individuals are also more likely to have sleep-related problems as a result of obstruction to their air passages in the nose and throat region.

The latest recommendations state that those who will benefit from weight loss are those who are in the obese category with a BMI of greater than 30. However, overweight individuals (BMI of 25 to less than 30) who have at least one risk factor for heart disease, such as high blood pressure, high cholesterol, diabetes, elevated waist circumference or obesity-related medical problems will also benefit from weight reduction.

Weight management goals

The most important starting point for any successful weight management programme is to set realistic goals. While it is understood that the greater the weight loss, the greater the potential benefit, a realistic initial goal will be to set a target weight loss of 5-10 per cent within the first six months.

Sustainable weight-loss regimes require a net energy loss where calorie loss exceeds calorie gain. It is recommended that a net energy loss of at least 500 kilocalories (kcal) be achieved daily. Depending on the physical activity of the individual, this can usually be achieved with a daily calorie intake of 1,200-1,500 kcal/day for women and 1,500-1,800 kcal/day for men.

Generally, very low-calorie diets (below 800 kcal/day) are only to be commenced under medical supervision. In some individuals with pre-existing medical conditions such as Gilbert's disease, the individual can become jaundiced within a few days of starting on a very low calorie diet. As Gilbert's disease, a benign hereditary condition, has an estimated prevalence of 5-10 per cent of the population, proper assessment must be performed.

Comprehensive lifestyle approach

A comprehensive lifestyle approach is key to successful weight-loss programmes. Lifestyle adjustments should be made during regular face-to-face visits of at least fortnightly frequency. Such programmes must include a reduced calorie diet with a planned daily energy deficit of 500 kcal or more, commencement of a regular physical exercise regime beyond the individual's usual activity level, and motivational drivers for adherence to a reduced calorie and increased physical exercise regime.

Generally, a weight reduction of 5-10 per cent is achievable at the end of six months with adherence to such a programme. The weight loss will plateau, and weight will stabilise after six months. Further weight loss will require adjustments to the calorie intake and physical exercise to maintain further net energy deficits.

'Lazy' ways to lose weight

For those who are unable to achieve or maintain weight loss despite undergoing a comprehensive lifestyle programme, or require further weight reduction for health reasons, other adjunctive measures may be considered such as drug treatment with medication such as Xenical (orlistat). In recent years, there are newer drug choices used primarily in obese diabetics. They are also able to reduce weight in non-diabetics too. Two newer classes of drugs, the sodium-glucose co-transporter 2 inhibitors (SGLT2i) and glucagon-like peptide receptor agonists (GLP-1 RAs), are able to cause weight loss.

SGLT2i works by causing glucose to be passed out through the urine. Hence, the higher the liquid intake, the more urine you pass, the more the glucose loss, and the higher the calorie loss. If you lose more calories that you consume, you will lose weight. This "lazy" way to lose weight may make you feel hungry if the sugar level drops and this where the GLP-1 RAs come in to reduce your appetite and counter the hyperphagia that may occur.

One of the additional benefits of using SGLT2i and GLP-1 RAs is that they are effective in improving the liver in those with non-alcoholic fatty liver disease (NAFLD). This condition affects more than 25 per cent of the general population and is especially prevalent in the obese cohort. In those with severe obesity, the incidence of fatty liver can vary between 70 and 90 per cent. Severe NAFLD, characterised by inflammation, and finally hardening of the liver (fibrosis), can lead to more serious conditions such as liver cirrhosis and liver cancer. Hence, these drugs can kill two birds with one stone.

Weight reduction procedures

There are some who are unable to achieve sustainable weight loss despite comprehensive lifestyle adjustment and/or medication. For those in the categories of extreme obesity (BMI of 40 or more) or BMI of 35 or more in the presence of serious weight-related health problems such as type 2 diabetes, high blood pressure or severe sleep apnoea, weight reduction surgery (bariatric surgery) can be considered if there are no contraindications.

Bariatric surgery reduces the size of the stomach or reduces the capacity to absorb food, or a combination of both. The advantages of these surgeries are rapid weight reduction, significant decrease in death from heart disease, diabetes mellitus, and cancer. The net effect is a 40 per cent decrease in death.

An analysis of several databases by Henry Buchwald, published in The Journal of the American Medical Association in 2004, stated that almost two in three individuals had reduction in blood pressure, almost three in four had reduction in cholesterol, and diabetes improved or resolved in five out of six. Bariatric surgery has also been shown to benefit obese individuals with impaired heart function resulting from obesity.

However, the surgery is not without complications. The risk for complications and nutritional deficiencies increase with increasing complexity of the gastric bypass procedure, with up to 20 per cent of patients requiring corrective surgery for complications. Some may require lifelong medications and special diets. More than one-third of those who have gastric surgery develop gallstones. Nearly 30 per cent of patients develop nutritional deficiencies such as anaemia and osteoporosis.

Long-lasting weight loss

There is never an easy way to lose weight without restricting calorie intake and increasing physical activities. While becoming increasingly popular for removing fat, liposuction is not a recommended method of weight loss. It carries no evidence of sustainable health benefits and yet carries a real risk of serious complications, including death.

Ultimately, weight loss is a matter of will. I am reminded of an obese patient of mine who has been seeing me for 20 years. During his regular visit earlier in the year, he came for his regular review in my clinic and expressed delight with his significant weight reduction of more than 10kg within six months. After 20 years of obesity, he suddenly made a decision to walk 45 minutes on his treadmill machine every morning and night, and made a conscious effort to restrict his calorie intake. The result was a healthier person with normal BMI, achieved purely by willpower.

Remember that there is no easy way out, and spending thousands of dollars at a slimming centre or on slimming foods can rarely produce sustainable weight reduction without willpower.

• This article is produced on alternate Saturdays in collaboration with MWH Heart, Stroke & Cancer Centre