Dietary carbohydrates may affect metabolic and physiologic parameters. The present study evaluated whether a combination of two dietary fibers, oligofructose (OFS) and pectin (P), altered satiety and glycemic parameters. The primary objective of this study was to determine whether dietary supplementation for 3 weeks with OFS + P would produce a greater reduction in energy intake of an ad libitum test meal compared to control.
This was a single center, randomized, double-blind, placebo-controlled, parallel group study in overweight and obese, otherwise healthy, subjects (N = 96). There were two OFS + P treatment groups: high-dose (30 g/d), low-dose (15 g/d), and a control group (maltodextrin 15 g/d). Energy intake, appetite measures based on Satiety Labeled Intensity Magnitude (SLIM) scale, fasting and post-prandial glucose, and insulin levels and body weight were measured at baseline and at the end of 3 weeks. Adverse events and gastrointestinal tolerability of the treatments were also assessed.
An analysis of covariance (ANCOVA) performed on the primary endpoint change from baseline in energy intake, showed no statistically significant difference in energy intake among the three treatment groups (p = 0.5387). The LS mean changes (SE) in energy intake from baseline to week 3 were -58.3 (42.4) kilocalories (kcal) for the high dose group, -74.2 (43.6) kcal for the low dose group, and -9.0 (42.9) kcal for the control group. For the pairwise comparisons of OFS + P doses and control, confidence intervals were constructed around the difference in LS mean changes. All study products were generally well tolerated.
There was a directional benefit in ad libitum energy intake for both OFS + P doses compared to control, with a greater reduction in kilocalories in the low dose comparison, but the reductions were not significant. Further studies are warranted.
Alex’s notes: We have all heard mom tell us to eat our vegetables, and no doubt the fiber content is one reason. They aren’t called “roughage” for nothing. That said, there are many different types of fibers and all plants have various amounts of each. Two such fibers are pectin which is found in fruits like apples, and oligofructose (OFS) which is found in legumes.
In the present study, 95 overweight but otherwise healthy men and women were divided into one of three groups: high fiber (5g pectin + 5g OFS), low fiber (2.5g pectin + 2.5g OFS), or control (no fiber). The fiber was consumed three times daily five minutes before each meal. This is the equivalent of eating an apple before a meal or having a salad appetizer.
Unfortunately, the fiber didn’t help with satiety and the groups still ate the same amount of food. Worse yet, 43% of the high fiber and 28% of the low fiber participants experienced GI distress (mainly gas, bloating, constipation, and diarrhea). In this regard, the study didn’t show what the researchers were hoping for. However, an unsung benefit was that insulin sensitivity improved in the fiber groups, as did the glucose surge into the bloodstream.
So fiber isn’t filling? Perhaps. But it may also be that the amount used was too low, as 15g of OFS has been shown to induce acute satiety (compared to the high-fiber group in the present study that only had 10g with each meal). Bottom line: fiber-up enough and you will get full, but if you eat to taste then enjoy the improved glucose disposal.