Monday, September 29, 2014

True or False: Foamy Slim.Fast is Better Slim.Fast | Stable Liquid Foams Increase Satiety by 50-100% | NO2-Aerated Foods Can Promote Dieting Efforts. Mechanism Unknown.

Would this work w/ this foam, as well?
We all know (hopefully) that there is not magic weight loss bullet, but who knows, maybe there is a magic weight loss foam... don't worry I am just kidding, but if you look at the data Sergey M. Melnikov et al. present in a recent study in the scientific journal Obesity, it looks as if foamy foods could be one out of many tools in your weight loss toolbox.

The scientists who work for Anglo–Dutch multinational consumer goods company Univlever conducted two randomized cross-over studies.
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In study one, the 24 volunteers the scientists had recruited for their trials consumed a full portion liquid (325 ml, 190 kcal) or aerated (1,000 ml, 190 kcal) of a commercial Slim.Fast drink at 0 min, or half portions of liquid (162 ml, 95 kcal) or aerated (500 ml, 95 kcal) of the same well-known diet beverage at 0 and 120 min.
Figure 1: Hunger scores as a function of time after ingestion of Lfull (liquid, 190 kcal, 325 ml), Afull (aerated, 190 kcal, 1,000 ml), Lhalf (liquid, 95 kcal, 162 ml), and Ahalf (aerated, 95 kcal, 500 ml) treatments (left) and corresponding area under the curve for the two treatments (Melnikov. 2014)
As you can see in Figure 1, the aeration of the Optima Milk Chocolate RTD from Slim.Fast (325 ml 330 g, 190 kcal, 15 g protein, 5 g fat, 21 g carbohydrates + vitamin/mineral mix) led to significantly more pronounced and sustained decreases in hunger compared to the non-aerated regular diet drink; and that in spite of the fact that both contained the exact same amount of nutrients and energy.
Want to make your own coconut foam? One you can use for your desserts like the chef who made the dessert on the left did?
Here is a guide that explains how you can create your own food foams. All you need is a compressed Nitrous Oxide dispenser and NO2 chargers. Well, and the ingredients you want to have in your foams, obviously.
Now, as usual, the question is: What's the mechanism of action, here? To answer this question and find out, whether it's just a question of volume or if the texture of the foam is involved in one way or another, Melnikov et al. conducted a second study. This time, the subjects consumed plain water that was either saturated with N2O or with CO2 10 min after a mini-drink (180 kcal). If it was just the NO2 there should be a similar increase in satiety as it was observed for the aerated Slim.Fast drink.

Is it the texture that makes the difference? Or is it just about volume? Or even the NO2?

As you can see in  (see Figure 2) this was not the case. The absence of significant effects suggest that the satiety effects is not simply attributable to any remarkable effect of the gas (N2O) that is added to the drink to create the foamy texture. That's in line with what the authors write about previous studies, ...
Figure 2: Hunger ratings in study 2 - no effect of NO2 alone vs. CO2  (Melnikov. 2014)
"[...which] have shown that entrapped air can effect an acute enhancement of satiety following single preloads of milkshakes (Rolls. 2000) or ready-to-eat cereals (Irvine. 2007), but effects are small and the duration of the satiety effects was not shown.

A small effect of carbonation on satiety has also been demonstrated over short periods and mainly seen with much higher gas volumes than used here (Moorhead. 2008)." (Melnikov. 2014)
Accordingly, the satiety effects may, as Melnikov et al. suggest, be attributable to the effect of aeration on gastric handling of the ingesta, which is related to an increased separation of nutrients in the stomach. Alternatively, the results could also be simply explained by the effect of the foam itself on gastric volume. If the latter was the case, results of previous studies would suggest that "the consumption of 1,000 or 500 ml foam would be sufficient to reduce eating motivations" (Melnikov. 2014).
Bottom line: The duration of the beneficial effects on satiety speak against the "increased gastric volume hypothesis", as it was far more pronounced than might be expected from previously published examples.

Can xanthan reduce the glycemic response to "sweet treats" like this?
In the end, we will probably need further studies to elucidate if there is an independent effect of textural food properties such as viscosity and hardness (liquid vs. semisolid vs. solid), which have been previously shown to influence the appetite and satiety response to foods (Martin. 2007). Until corresponding studies have been conducted, we are left with the intriguing insight that aeration of products with a particular composition, structure, and stability can dramatically enhance the degree and duration of post-meal suppression of eating motivations and could thus help overweight and normal-weight individuals, alike, to control their food intakes and body weight | Comment on FB!
References:
  • Irvine, Paul, Barbara Livingstone, and Robert Welch. "Bulk density of ready-to-eat cereals affects satiety and subsequent intakes in young women." International Journal Of Obesity. Vol. 31. Macmillan Building, 4 Crinan St, London N1 9xw, England: Nature Publishing Group, 2007. 
  • Martin, Corby K., et al. "Slower eating rate reduces the food intake of men, but not women: implications for behavioral weight control." Behaviour research and therapy 45.10 (2007): 2349-2359. 
  • Melnikov, Sergey M., et al. "Sustained hunger suppression from stable liquid food foams." Obesity (2014).
  • Moorhead SA, Livingstone M, Dunne A, Welch RW. "The level of carbonation of a
    sugar-sweetened beverage preload affects satiety and short-term energy and food
    intakes." Br J Nutr 99 (2008):1362-1369.
  • Rolls, Barbara J., Elizabeth A. Bell, and Bethany A. Waugh. "Increasing the volume of a food by incorporating air affects satiety in men." The American journal of clinical nutrition 72.2 (2000): 361-368.