Picking and choosing: No way to lose weight

Medical Tribune May 2009 P13
David Brill

Weight loss diets which promote one particular food group may not be the best way to shed the kilos, a recent study suggests.

In one of the longest trials of its kind, US researchers found that there was ultimately little difference in weight loss whether diets emphasized carbohydrates, protein or fat.

Nor did waist circumferences differ significantly after 2 years of following the diets, the study of 811 overweight adults showed.

"This is important information for physicians, dieticians and adults, who should focus weight loss approaches on reducing calorie intake," said lead author Professor Frank Sacks, Harvard School of Public Health, US.

Participants were randomized to one of four diets. The compositions varied, but all targeted a 750 kcal decrease in daily intake. [N Engl J Med 2009;360(9):859-73]

Weight loss peaked at 6 months – when participants had lost an average of 6 kg, or 7 percent of their initial weight. Weight regain began after 12 months: those who completed the study had lost an average of 4 kg at its conclusion.

The researchers also found that people who attended the most group counseling sessions lost the most weight – an average of 0.2 kg per weekly session.

"These findings suggest that continued contact with participants to help them achieve their goals may be more important than the macronutrient composition of their diets," said Sacks.

Singapore’s Health Promotion Board (HPB) welcomed the study as an informative, but not definitive, addition to the literature.

“The study was limited in that the differences in the macronutrient content of the different diets was not as substantial as originally planned, hence the resultant diets did not fully replicate the macronutrient distribution of popular ‘low-carb’ or low-fat diets,” said Mr. Benjamin Lee, manager and nutritionist, adult health division, HPB.

The HPB advocates a holistic approach to weight loss including exercise and stress management, added Lee. Specific dietary recommendations are to focus on calorie reduction while maintaining a diet which covers four food groups: rice and alternatives, fruit, vegetables, and meat and alternatives (including dairy foods).

Ms. Jamie Liow, a nutritionist and member of the Singapore Nutrition and Dietetics Association, said that carbohydrate intake is typically a concern among Asians who diet.

“Most would either have a low-carbohydrate, high-protein diet, or no carbohydrates at all. Crash dieting seems to be popular among younger girls as well,” she said.

Liow also emphasized the importance of getting nutrients from “a whole spectrum of foods,” adding that doctors should refer their patients to dieticians for specific advice on the best way to lose weight.

The four diets tested by Sacks et al. comprised: 20 percent fat, 15 percent protein and 65 percent carbohydrate; 20 percent fat, 25 percent protein and 55 percent carbohydrate; 40 percent fat, 15 percent protein and 45 percent carbohydrate; or 40 percent fat, 25 percent protein and 35 percent carbohydrate.

The lowest-fat and the highest-carbohydrate diets brought about the greatest reduction in LDL cholesterol levels, whereas the lowest-carbohydrate diet yielded the biggest increase in HDL cholesterol. Triglyceride levels dropped similarly for all diets.

Dieters were also encouraged to exercise for 90 minutes per week, and received weekly group counseling sessions and 8-weekly individual sessions.

Despite this intensive encouragement, dieters did not meet their nutrient intake targets when questioned at 6 months and 2 years. This appears to be a common problem in weight-loss trials, say the authors, noting that many previous studies have also found that adherence declines after a few months.

Lifestyle program boosts diabetes control in overweight Chinese

Medical Tribune March 2009 SFV
David Brill

An integrated lifestyle intervention program, including dietary supplements and meal replacements, can help overweight Chinese diabetics lose weight and improve glycemic control, a new study has shown.

Patients who followed the program for 24 weeks lost an average of 2.7 kg and saw their HbA1c drop by 0.8 percent compared to baseline (P<0.001).>

Such were the benefits of the intervention that 15 of the 100 type 2 diabetics who followed it had had their diabetes medication dosages reduced by the end of the trial, while a further seven stopped taking them altogether.

The results of the study, led by Dr. Jianqin Sun of Fudan University, Shanghai, were announced at a recent Singapore press conference and published in the Asia Pacific Journal of Clinical Nutrition. [2008; 17(3):514-24]

The intervention program included diabetes education, nutritional counseling, meal replacement with dietary supplements, and weekly progress reports with a physician and a dietician. It was compared in a randomized prospective trial against a simpler intervention comprising only education on diet and physical activity. Fifty patients were included in this reference group.

Professor William Garvey, a US diabetes expert who commented on the study, described the reduction in HbA1c as “very impressive” given that the intervention patients were already well-controlled, with an average HbA1c of 7.1 percent at baseline. He also noted that the potential to reduce or stop medications provides a good incentive for diabetic patients to lose weight, but stressed that these adjustments should only be made following proper consultation with a physician.

Dr. Kevin Tan, vice-president of the Diabetic Society of Singapore, said that the study demonstrates the viability of meal supplements as a therapy for diabetes, adding that this option should be explored for all patients who are overweight.

“Meal supplements or replacements have not been talked about much so a lot of doctors don’t think about them, but they do play a part in diabetes management in terms of helping to reduce calorie intake and helping patients to lose weight. If GPs realize that this can be part of their usual holistic diabetes care, along with the medications, exercise and weight control, then I think it will help to improve sugar control in their diabetic patients,” he said.

Participants in the study were all type 2 diabetics aged 18 to 70 with a BMI of 23 kg/m2 or above. The lifestyle intervention also significantly improved blood pressure (BP), with patients in this group recording average reductions of 7.5 mmHg for systolic BP and 3.4 mmHg for diastolic BP, at 24 weeks as compared to baseline. These reductions were significantly greater for the intervention group compared to the reference group.

The waist-to-hip ratio was also reduced among patients in the intervention group compared to those in the reference group.

“Dietary supplements are not the magic answer for everybody but they can be helpful in many patients,” said Garvey, who is based at the University of Alabama at Birmingham, US.

“If you have a patient who needs to lose weight and you feel that they need more structure in terms of their dietary plan – less guesswork and more clear-cut guidance in terms of what the diet will be from day to day – a meal replacement is a really good tool to use,” he said.

Garvey acknowledged that the short duration of the trial makes it hard to assess the long-term sustainability of the intervention, but added that the structured nature of the program teaches important behavioral modification skills which continue to be applicable beyond the trial setting.

The burden of type 2 diabetes in China is increasing rapidly, according to the study authors, who note that the prevalence among large city residents rose from 4.6 percent in 1995 to 6.4 percent in 2002. In Singapore the burden could be even higher, with data from the 2004 National Health Survey suggesting a diabetes prevalence of 8.2 percent among residents aged 18 to 69.

The trial by Sun et al. was funded by Abbott Laboratories, which manufactures the dietary supplement used in the study.

Beating childhood eating disorders: Mum’s the word

Medical Tribune December 2008 SFX

David Brill

Physicians can help children overcome eating disorders by taking a tactful, measured approach to worried mothers, an international expert said on a recent visit to Singapore.

Some 25 percent of children are thought to have a feeding disorder, the long-term consequences of which can include growth problems and an increased susceptibility to chronic diseases. [J Clin Gastroenterol 2000 Jan;30(1):34-46]

The majority of children, left to their own devices, will simply grow out of it, according to Dr. Benny Kerzner, a professor of pediatrics at the George Washington University School of Medicine, US. The problem, however, can be worsened if the parents’ minds are not put at ease.

"The trouble is the anxiety effect. These parents, even if their kids are doing nutritionally well, bring an intensity to their feeding which becomes a problem. The mothers are fearful and the resulting meal conflict has negative consequences."

It is common for mothers to be concerned about their child’s eating habits: a study by Abbott Nutrition shows that two in five consider their child to be a fussy eater, with 55 percent coaxing or enticing them to eat certain foods.

This anxiety is typically borne out of a fear that if the child is undernourished their development will be stunted, Kerzner said. Research shows, however, that psychosocial factors such as mother-child interactions actually have a greater impact than nutritional status on the cognitive development of toddlers with eating disorders. [Pediatrics 2004 May;113(5):e440-7]

Concerned mothers will often consult their GP or pediatrician, which provides the ideal opportunity to allay their fears, Kerzner said.

"The doctor needs to be empathetic, and needs to be certain that he’s not slighting the issue. You don’t want to make too much of a big deal out of it but you want to be knowledgeable enough to tell her why she can relax."

The doctor should begin by taking a thorough history in order to rule out genuine medical explanations such as allergies, pain with swallowing, or gastroesophageal reflux, Kerzner said.

"You’ll then be left with a large number of children where the mother is still concerned. Those I divide into two: the children who primarily have an appetite issue and, at the other end of the spectrum, the kids with sensory issues."

For children in the first group the doctor can teach some basic appetite-enhancing techniques or "food rules," such as stopping snacking between meals, limiting the size of meals, avoiding distractions at mealtimes and adopting a neutral attitude so that the child does not feel pressured to eat.

Sensory issues such as neophobia – the fear of new things – can be overcome by introducing new foods slowly and gradually, Kerzner said, adding that parents need to show genuine persistence and not lose heart if the child rejects a new food two or three times.

Doctors can also use growth charts to demonstrate to parents that their child is developing normally. In some cases they may also wish to recommend a dietary supplement or, if the problem persists, refer the child to a dietician, he said.

"In order to put them at ease you can’t fool them. What we need to have is a genuine discussion explaining the attitude that we have and why we’re not worried," Kerzner concluded. He was speaking at a press conference organized by Abbott Nutrition.

Unhealthy diet raises heart attack risk by 35 percent

Medical Tribune December 2008 SFXIV

David Brill

Eating a diet high in salt and fried foods can increase the risk of acute myocardial infarction (AMI) by as much as 35 percent, according to a large-scale study conducted across 52 countries worldwide.

The analysis of 5,761 AMI cases and 10,646 controls from the INTERHEART study also highlighted the benefits of eating fruit and vegetables – a dietary pattern that reduced AMI risk by 30 percent.

The chairman of the Singapore Heart Foundation, Dr. Terrance Chua, said that the findings should serve as a warning to Singaporeans, who are increasingly moving towards the unhealthy diet described in the paper.

"This is a message that all the various health promotion bodies in Singapore have been advocating all along, but knowledge is one thing and actual practice is another. Changing behavior is a real challenge," he said.

Chua hailed the global scale of the study as "very significant" since most previous research in this area had been limited to Western countries.

"This allows us to extend those results to different populations and different ethnic groups," he said.

"In a way it’s confirmed our understanding that high fat, salty snacks and dairy products are associated with an increased risk. Unfortunately that’s the diet that everyone in the world is tending to develop because it’s seen as the diet of successful societies."

The National Nutrition Survey of 2004 showed that although Singaporeans are eating more fruit and vegetables they are also consuming more fat, an increasingly high proportion of which is saturated.

Dr. Seow Swee Chong, a consultant cardiologist at National University Hospital, agreed that the findings from the INTERHEART study are a concern for Singaporeans but was more cautious in his appraisal of the research.

"This study is hypothesis-generating but not conclusive," he said, adding that the exact extent to which diet influences risk remains unclear since there are several limitations to the paper.

"The type of diet is undoubtedly influenced by the region that the study subject is from and also his ethnicity. Thus the findings may reflect more of a difference in propensity towards AMI due to genetic, racial or geographical factors rather than the diet. Indeed, there was a significant interaction between diet and region in the study," he said.

Participants in the case-control study were enrolled at 262 centers between February 1999 and March 2003. Dietary patterns were assessed using a 19-item food frequency questionnaire. [Circulation 2008 Nov 4;118(19):1929-37]

The international research team, led by McMaster University and Hamilton Health Sciences, Ontario, Canada, divided diet into three types: ‘prudent’ – high in fruit and vegetables, ‘Western’ – rich in fats, meat and salt, and ‘Oriental’ – high in tofu, soy and other sauces.

The adjusted odds ratios for AMI were 1.35 and 0.70 for those in the highest quartile
of adherence to the Western and prudent diets, respectively, compared to those in the lowest quartile (P for trend <0.001).>

Chua and Seow, however, both expressed reservations about the arbitrary classification system employed by the authors, preferring instead to focus on the components of the diet.

"It’s important not to be confused by the labeling and think that a Western diet is unsafe but it’s fine to eat nasi lemak and chicken rice," said Chua, noting that Asian food often contains just as much fat as Western food.

Mediterranean diet reduces diabetes risk

Medical Tribune August 2008 SFXV
David Brill

Following a Mediterranean diet – known to lower cardiovascular risk – can also reduce the chance of developing diabetes, Spanish researchers have shown.

The study, which was published in the British Medical Journal, followed 13,380 university graduates over a median period of 4.4 years and used questionnaires to rank their adherence to the diet on a scale of one to nine.

“Those who were highly adherent to this traditional dietary pattern exhibited a very low rate [of diabetes] and an impressive magnitude in the relative risk reduction of 83 percent,” said lead researcher Miguel Martinez-Gonzalez, Professor of epidemiology at the University of Navarra.

Interestingly, he added, people who adhered most closely to the diet were typically older with a higher prevalence of hypertension, smoking history and other risk factors for diabetes. The incidence among this group would therefore have been expected to be high.

“This may mean that the Mediterranean diet is highly protective against diabetes,” he said, but added that only 33 new cases were observed – a small number relative to the size of the study.

“This is fortunate for our participants indeed but this is a major limitation. We need further evidence from larger cohorts and trials,” he said.

The traditional Mediterranean diet comprises high amounts of olive oil, fruit, vegetables, nuts and fish, and relatively low amounts of meat and dairy products. The health benefits of the diet have been shown in various studies, including a randomized trial which demonstrated a beneficial effect on cardiovascular risk factors. [Ann Intern Med 2006 Jul 4;145(1):1-11]

Dr. Warren Lee, former Chairman of the Diabetic Society of Singapore, said that the study was interesting and comprised good quality data.

“I would certainly say this reinforces the old chestnut that one should take more fruit and vegetables and emphasize less on the meat,” he said.

It remains unclear at what point of adherence to the diet the benefits begin to accrue, added Lee, who is a pediatric endocrinologist in private practice and a senior consultant at KK Women’s and Children’s Hospital.

"This study was not able to show a threshold effect because it was designed to show that there was an effect in a relatively homogenous population of people who ate either more than the mean or less than the mean of certain foods.

“However it was heartening that a two point increase in a nine point score was able to reduce the incidence rate ratio – a measure of relative risk – by 35 percent, and that even those in the moderate adherence group had a significant benefit. This suggests that people trying to adhere to a healthy diet will be better off than those who do not even try,” he said.

Lee noted that the diet in Spain is rather different to that in Singapore, where food is frequently cooked using palm oil or pork lard rather than olive oil.

“Perhaps the next step is to see how we can incorporate elements of this diet into our food choices,” he concluded.