|About to go for a walk? Have fructose for breakfast to keep the hunger at bay.|
As a SuppVersity reader you will know that low-intensity cardio, much more than HIT or HIIT (learn more), will trigger significant increases in hunger and one's desire to eat. To ameliorate this effect, you could - that's at least what the aforementioned study shows - simply replace part of the starchy or high GI carbs of your breakfast with high fructose fruits and/or other fructose containing food items.... that's at least - as previously mentioned - what the study at hand suggests; a study in which Hong Kong researchers compared the effects of three isocaloric breakfasts with identical amounts of carbs (1.0 g/kg body weight) from different food sources with different GIs (41, 39, and 72) and fructose contents on the appetite scores of ten healthy young male volunteers (21.7 ± 1.5 yr, 20.9 ± 1.1 kg/m²) who had to rate different aspects of appetite every 30 min during the 2-hr postprandial period after the meal, as well as during the 1-hr recovery period that followed the 1h of brisk walking (46% VO2max) all subjects had do perform 2h after consuming the standardized breakfasts.
"Three isocaloric meals were used in the present study. [...] Briefly, all meals had similar macronutrients and provided 1.0 g∙kg−1 body weight CHO for each participant. The LGI meal was composed of cooked spaghetti, egg, and full-fat milk. The LGIF meal comprised rice vermicelli, egg, ham, and fructose. The HGI meal involved rice vermicelli, egg, ham, and glucose. In the LGIF and HGI meals, approximately 25% of energy was derived from the fructose or glucose beverage (nearly 25 g for a 60 kg person). The calculated GI values for the LGI, LGIF, and HGI breakfasts were 41, 39, and 72, respectively. All meals were freshly prepared in the morning of each main trial, and the preparation procedure was standardized."As you can see in Figure 1 the three test-meals initially had very similar effects on the subjects' appetite ratings, i.e. their desire to eat, hunger, fullness, and perceived ability to eat.
|Figure 1: Appetite Sub-Score. b: P < 0.05 vs. LGIF. LGI: Low-GI meal without fructose; LGIF: Low-GI meal including fructose beverage; HGI: High-GI meal (Sun. 2015).|
|Figure 3: The appetite suppressing effects of fructose preloads in the absence of exercise have been known ever since Rodin's 1990 study on the effects of fructose vs. glucose and water preloads on food intakes (Rodin. 1990).|
"[t]he effect of fructose on appetite has been substantially investigated. Earlier studies have indicated that fructose beverages suppressed energy intake more than glucose beverages did (Rodin, 1990 and Rodin, 1991). The underlying mechanism has been attributed to the metabolism of fructose in the liver and the effect of insulin" (Sun. 2015).In fact, scientists have previously speculated that fructose may affect appetite through slow and incomplete absorption. This effect, however, is eliminated when fructose is consumed with other CHOs (Anderson. 2003). As far as potential mechanisms are concerned, we are thus left with changes in satiety hormones and peptides like ghrelin, cholecystokinin, glucagon-like-peptide-1 and peptide-YY and/or direct or indirect effects on the gut-brain axis as potential mechanisms that would explain the results of Sun's study. Unfortunately, neither of these mechanism was assessed in their study.
- Anderson, G. Harvey, and Dianne Woodend. "Effect of glycemic carbohydrates on short-term satiety and food intake." Nutrition Reviews 61.5 (2003): S17.
- Blundell, John E., and Neil A. King. "Physical activity and regulation of food intake: current evidence." Medicine and science in sports and exercise 31 (1999): S573-S583.
- Lowette, Katrien, et al. "Effects of high-fructose diets on central appetite signaling and cognitive function." Frontiers in nutrition 2 (2015).
- Melzer, Katarina, et al. "Effects of physical activity on food intake." Clinical nutrition 24.6 (2005): 885-895.
- Rodin, Judith. "Comparative effects of fructose, aspartame, glucose, and water preloads on calorie and macronutrient intake." The American journal of clinical nutrition 51.3 (1990): 428-435.
- Rodin, Judith. "Effects of pure sugar vs. mixed starch fructose loads on food intake." Appetite 17.3 (1991): 213-219.
- Sun, Feng-Hua, Stephen Heung-Sang Wong, and Zhi-Gang Liu. "Post-exercise appetite was affected by fructose content but not glycemic index of pre-exercise meals." Appetite 96 (2016): 481-486.