Ingrid Schloss, a clinical dietitian, responds to Professor Tim Noakes's letter, Virta Health study vindicates Banting, and draws attention to 'a much larger, well powered randomised clinical trial' with its findings on the carbs vs fat issue.
Ingrid Schloss, writes:
“With reference to last week’s letter by Professor Tim Noakes that Virta Health study vindicates Banting. Like many studies, it contributes to the growing body of evidence around dietary modification and health parameters.
Here is another one: – a much larger, well powered randomised clinical trial published recently (Gardner et al, JAMA 2018), which recruited 609 participants; retained and tracked them over a long period of time (12 months) and carefully monitored compliance to individuals assigned either a healthy low fat or healthy low carbohydrate diet.
The clear outcome of the study was that both groups lost weight but that there was no significant weight-loss differences between the healthy low-fat and healthy low-carb diets, possibly because the groups spontaneously ended up with similar calorie deficits to their original diet. Furthermore, health markers such as BMI, body fat percentage, waist circumference, blood pressure, and fasting insulin and glucose levels were improved in both groups but there were no significant differences between the groups suggesting they were equally effective.
Notably, the same emphasis on healthier, high dietary quality in both groups [namely minimise or eliminate refined grains and added sugar, maximise vegetables and emphasize home cooked foods] may well be a contributing factor to the outcomes found in this well-designed study. Aspects around the sustainability of specific eating plans were explored which is a realistic aspect of theoretical research objectives and is a vital component for life long compliance.
I mention this merely to remind the public and health professionals of the extreme complexity of nutrition in the aetiology and management of lifestyle – related conditions and that there will never be one size that fits all. Furthermore, individuals are rather much more complex cases of differing ages, cultures, genetic backgrounds and potential underlying conditions (often unknown) which can be triggered by extreme dietary modifications of any kind.
Instead of continuing to publicly vilify the dietetic profession, and adopting fundamentalism in dietary approaches – how much more refreshing it would be if we could focus on more positive foundation nutritional messages (highlighted in this study) which are generally agreed to by most nutrition bodies – namely reduce added sugar and refined grains; choose more whole foods, and include a wide variety of vegetables.
Additional nuances to dietary modification should continue to be done on an individual basis in order to consider the full context of the individual – whether that be for weight management, diabetic management or weight gain in cancer patients. This is more likely to ensure maximum benefit and more importantly to minimise harm in a way that would be considered not only professional, but ethically responsible.”
[link url="http://2018/02/low-fat-or-low-carb-its-a-draw-study-finds.html"]Stanford University material[/link]
[link url="https://jamanetwork.com/journals/jama/article-abstract/2673150?redirect=true"]JAMA abstract[/link]