Medical science has published many papers on the health effects of dietary fibers.   While the active constituents in various fibers yield different pharmacological effects, pre-biotic  (resistant starches) fibers from foods like green bananas, cold potatoes, tapioca, chicory root, corn fiber or Psyllium fiber, that has some interesting effects for ultra-endurance athletes.

Most interesting for the endurance athlete looking to become keto-adapted (i.e. efficiently oxidize fat for fuel) is the ability of these fibers to reduce post-meal blood glucose, insulin concentrations and thereby raising AMPK (adenosine monophosphate-activated protein kinase) levels.  One of the key functions of AMPK in the body is its role in the creation of new mitochondria (the powerhouses of energy production) and more efficient oxidation of fat for fuel.

In one study involving diabetic patients (non-insulin dependent), prebiotic fibers showed a 14% reduction of insulin production after a breakfast meal, and 20% reduction for dinner. The more we keep blood-sugar and insulin levels down, the more the body will rely on fat, as the preferred and prime energy source to fuel body activity.

Insulin inhibits AMPK, a master enzyme that facilitates the take up of glucose and switches on fat burning.  Pre-biotic fibers will increase short-chain fatty acids like Butyrate in the gut, which in turn has been shown to elevate the levels of AMPK in the body. Dark pigmented fruit-vegetable skins containing Cyanidins (grapes, berries etc.) and extracts like Resveratrol, and Quercetin contain AMPK stimulating compounds which can raise mitochondrial density in cells.

Aside from reducing insulin levels (and increasing fat utilization for energy), a more stable blood sugar/insulin level, will help us avoid those dreaded sugar-binges.  However, for most people, the mid-morning snack is part of our daily routine – and in a lot of cases, it’s typically higher in carbs and bad fats. So what’s the role of pre-biotic fibers here ?

Well, triple-blind cross-over studies have shown, that the addition of pre-biotic fiber rich foods caused a significant difference in the sense of ‘fullness’ 1hr post-meal (breakfast etc.), and furthermore the total amount of fat intake (for the day) following the use of the prebiotics, was lower versus taking water.

But even in the case where, a high-glycemic food is eaten, adding prebiotic foods to the meal significantly reduced in-vitro (in test-tube) and in-vivo (in human body)  blood sugar responses.

So, adding these ultra high impact prebiotic fibers, to your breakfast, lunch, dinner and training foods will pay high dividends in keeping insulin lower, higher fat burning and increasing AMPK activity.

Go Longer.  Thanks for reading.

1.  Psyllium fiber reduces rise in postprandial glucose and insulin concentrations in patients with non-insulin-dependent diabetes.  Pastors JG.  Jun 1991.
2.  Effects of psyllium on glucose and serum lipid responses in men with type 2 diabetes and hypercholesterolemia.  Anderson JW. Oct 1999.
3. Psyllium decreased serum glucose and glycosylated hemoglobin significantly in diabetic outpatients.  Ziai SA. Nov 2005.
4.  The effect of a Plantago ovata seed containing preparation on appetite variables, nutrient and energy intake.  Turnbull Wh. May 1995.
5.  Impact of dietary fiber-enriched ready-to-eat extruded snacks on the postprandial glycemic response of non-diabetic patients. Brennan MA. May 2012.
6. Butyrate Improves Insulin Sensitivity and Increases Energy Expenditure in Mice. Zhanguo G et al.  Jul 2009.
7. Regulation of mitochondrial biogenesis. Jornayvaz FR et al.  Jan 2014.