More complex carbs lead to lower body fat

Posted in Latest Research ... October 23rd, 2010

Recent research*, due to be published in the November issue of The American Journal of Clinical Nutrition, has shown that a diet high in wholegrains and low in refined grains leads to a reduction in a type of fat that has been linked to cardiovascular disease and Type 2 diabetes. The study showed that eating at least 3 servings of wholegrains each day led to a 10% reduction in Visceral Adipose Tissue (VAT), only when combined with limiting intake of refined grains to less than 1 serving per day. 1 serving of wholegrains is equivalent to one slice of wholemeal bread or half a cup of oatmeal while 1 serving of refined grains equates to 1 slice of white bread or half a cup of white rice.VAT is a type of fat that surrounds organs in the abdomen and is different to the type of fat we normally think of, namely, Subcutaneous Adipose Tissue (SAT), that lies just under the skin. VAT can lead to increased levels of bad (LDL) cholesterol and insulin resistence that in turn contribute to metabolic syndrome and Type 2 diabetes.

Just Nutrition Viewpoint

This study is interesting because, while it has long been accepted that eating wholegrains is good for health, particularly heart health, it has not been generally known that this effect is dependent upon simultaneously restricting refined grains in the diet. These foods lack the fibrous outer coating which is not only a source of vitamins & minerals but also helps buffer the release of sugar into the blood. Such foods cause a rapid rise in blood sugar which causes the pancreas to release insulin in order to return the blood sugar to normal. Insulin resistence occurs when the cells become insensitive to the effects of insulin causing the pancreas to produce higher and higher amounts of insulin.  Eventually the pancreas becomes exhausted and is unable to produce enough insulin to keep blood sugar within normal range leading to persistently high levels and Type 2 diabetes.

Together with a diet high in refined carbohydrates and sugar, metabolic syndrome and Type 2 diabetes are caused by high levels of ‘bad’ fats in the diet, namely, saturated, ‘trans’ and hydrogenated fats. While fat is an essential component of a healthy diet, it should be from ‘good’ fats, primarily Omega 3 and Omega 9’s. Omega 3’s are found in oily fish, flax seeds and flax seed oil as well as nuts and seeds. Omega 9’s are found mainly in olive oil. Saturated fat is found primarily in meat and dairy products, ‘trans’ fats in fried foods and hydrogenated fats in processed foods such as cakes, biscuits and ready meals. All should be kept to a mimimum in the diet. Sugar and alcohol cause a rise in blood triglycerides (fats) that also promotes heart disease and insulin resistence.  

*Whole- and refined-grain intakes are differentially associated with abdominal visceral and subcutaneous adiposity in healthy adults: the Framingham health study. The American Journal of Clinical Nutrition Vol. 92, No. 5, 1165-1171, November 2010