COULD increased fibre consumption over long periods help obese people lose weight?
It’s a question being posed by a research team, headed by Associate Professor Sebely Pal, at Curtin University’s School of Public Health, after it previously found fat levels in blood were reduced by 24 per cent when people ate a high-fibre breakfast.
“It’s been suggested fibre controls body weight by affecting food intake, having some effect on the subjective feeling of fullness and reducing appetite,” A/Prof Pal says.
“The chemical structure of the fibre and their physicochemical properties—such as solubility, viscosity, water-holding capacity and fermentability—might be related to its effect on appetite control, energy intake and body weight.
“Mechanisms may also include its effects on gastric emptying, satiety, gut hormones such as cholecystokinin and an altered glycaemic index or insulin response.
“When consuming fibre, the act of chewing takes longer and this seems to increase sensory satiety and diminishes the size of the meal.”
Dietary fibres also reduce the energy density of the specific food, which may directly cause a lower energy intake and indirectly decrease appetite.
It’s also believed dietary fibre decreases energy absorption by lowering the bioavailability of fatty acids and proteins.
“Dietary fibre has been shown to cause favourable changes in circulating lipid and lipoprotein levels, including reductions in low-density lipoprotein (LDL), serum triglyceride (TG) and serum total cholesterol levels and increases in high-density lipoprotein (HDL) concentrations, all independent risk factors of cardiovascular disease,” A/Prof Pal says.
“Fibre seems to decrease glucose levels and increase insulin action, promoting beneficial effects to overweight and obese individuals, as well as those with diabetes.
“As fibre forms a viscous gel in aqueous solution, it may slow the access of glucose to the small intestine's absorptive epithelium, thereby blunting postprandial glucose peaks.”
While high-fibre diets, such as The F Plan Diet, may have been all the rage in the 1980s, A/Prof Pal says some diets considered trends in the past are now being scientifically substantiated.
“Epidemiological, cohort and clinical studies have consistently revealed that higher fibre intakes lead to a lower body weight, body mass index and waist circumference,” she said.
“It also improves plasma lipid profiles, glycaemia and insulinaemia, indicating the benefits and risk reduction for metabolic syndrome, cardiovascular disease and type 2 diabetes.
Volunteers are needed for the fibre research and must be between 18 and 65 with a body mass index (BMI) of more than 25 and less than 40.