PROTEIN

Finally I get to post about something not too many people are questioning..Protein overconsumption! 😀

Whether I talk to a body-builder or a dietician, health effects of eating too much protein do not seem to be on anyone’s radar (unless a kidney disease is suspected).

Beef it up!
In developed countries people are eating approximately 30% more protein than the RDA recommended intake (1.2g of protein/kg of body weight/day vs. 0.83g RDA). Yet this is considered harmless or even beneficial (for satiety, obesity prevention). In general, we can think of all kinds of anti-fat or anti-sugar arguments, yet protein seems to be the nutrient we don’t need to worry about. There are many protein-enriched snacks and drinks that seem to have a health halo effect. I think people are not even sure why the label claim “x grams of protein!” seems exciting or promising some sort of a benefit (unless one is a gym enthusiast). Perhaps it is the fact that we don’t know any “bad” health effects of this nutrient.

Longevity & health studies
In terms of living longer, calorie restriction(CR) is the only non-genetic intervention that can lead to life extension in different organisms (from yeast to rodents to monkeys and supposedly humans). Calorie restriction means reduced energy intake (moderate CR is about 30% less calories than recommended) without malnutrition. Studies on the famous Okinawa centenarians suggest it is their moderate eating that contributes to health and longevity.
So CR should not be confused with starving or extreme undereating- many people and cultures might do so without much thought- eating about 1700 calories/day for a person with 2000 being a goal is already calorie restriction.

In mice CR studies, general CR increases longevity and induces a reduction in the level of IGF-1 (insulin-like growth factor 1). IGF-1 is an important growth factor that mediates the growth of cells and inhibits apoptosis (cell death); it is IMPORTANT because there is considerable evidence that a reduction in IGF-1 signaling plays a key role in modulating cancer and aging in humans and rodents. HOWEVER, for us humans CR does not reduce IGF-1 concentration unless protein intake is also reduced. This suggests that protein intake is more important than calorie intake in terms of IGF-1 levels in humans.

Median protein requirement for a healthy adult, by the way, is 0.65 g/kg/day. Decreased protein intake discussed with CR does not go below this number.

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mTOR
I first came across the idea of not going crazy on the protein while reading about mTOR. The mammalian target of rapamycin (mTOR) signaling system seems  to be connected with aging and cancer
development (also cardiovascular and neurodegenerative diseases). The insulin/IGF-1/mTOR pathway is downregulated by calorie restriction, and in turn activates other anti-aging pathways in mammalian cells.

Conclusion
It is necessary to see more human studies with caloric and protein restriction and the effect on health and longevity. We all know overeating is not great- it does lead to weight gain and associated health issues. But it also might be speeding up our aging, wear&tear, and increasing chances of various chronic diseases. This could be crucial for a culture that believes protein to be a healthy macronutrient which needs no limitation 😉

Some LINKS:

Why Protein is the new “It” Ingredient

http://online.wsj.com/article/SB10001424127887324789504578384351639102798.html

Macronutrient Balance and Lifespan

http://www.impactaging.com/papers/v1/n10/full/100098.html

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Shall we Snack?

How we think about the food we eat matters. Really matters. The way you categorize your food- whether it qualifies as a meal or a snack- can influence whether & how much you will eat later that day.

Today we talked about snacks in the psychology of eating class. My personal cross-cultural observation of snacking between Ukraine and US is that Americans tend to snack more often.. they snack in various situations (at work, in class, on the run) and some believe snacking throughout the day is beneficial for weight maintenance. This perception comes from the idea that eating more small meals throughout the day (snacking) will keep your metabolism up or keep your hunger down. While it does elevate your metabolism somewhat, the problem is that most people can’t seem to eat “small” meals throughout the day… instead they end up simply eating all day long. In terms of hunger management.. it is quite individualistic- perhaps having a snack truly makes you less hungry throughout the day…or it makes you even hungrier (now, that depends on the snack too; carb-rich snacks tend to make us hungrier after consumption…and we can argue that processed foods have an addictive quality where you just have to finish the whole bag).

SNACK vs. MEAL

What’s a snack? Usually something small or in pieces.. it is eaten between meals. If you’re surprised by how someone might confuse a meal with a snack- people do think differently about which is which…some foods can be seen as both by different people- e.g. pizza or bagels (hey, some eat cereal for dinner!). Generally, though, “snack food” is perceived as food  not consumed to satiation (versus a meal); it also involves eating alone and for a short period of time.

A study by the ASU provost/my psychology professor Capaldi* showed that the cognitive feature of food (whether you perceive it as being part of a meal or a snack) moderates food intake regardless of hunger and satiety following a load. In simpler terms- if people ate the same amount of calories, but perceived the food as a SNACK, they ate more afterwards (even though their satiety level was the same as for those consuming the same food only seen as a MEAL). It has to do with norms- we feel it is much more appropriate to eat a full meal after some snacking then after a meal.

PROBLEMATIC DEFINITION
So your categorization of food might be important for how much you eat…This might be a problem with the way eating has evolved lately. Meals are generally seen as a sit-down occasion with utensil use…but in the hectic modern life your lunches and dinners might not involve a plate, fork, or even sitting down to eat. As a result, you might not register your lunch as a satiating meal and feel the need to eat later. Indeed, taking the time to eat in a calm atmosphere might make you feel more satisfied with your meal (has anyone else ever felt like they didn’t really eat if they grabbed something on the fly? I definitely do).

Shall we snack!? Currently,  evidence does not support many theories that encourage increasing frequency of eating for weight management**. Some suggest that snacking is one of the main causes of overconsumption and obesity***. In the end, you can’t recommend the whole population to either snack frequently or avoid it altogether. Some might find snacking to keep their appetite down.. while for others it may be difficult to control food quantities once they commence eating.  I suppose you should go with your gut and be mindful of whatever you are eating 😉

* Capaldi, E. D., Owens, J. Q., & Privitera, G. J. (2006). Isocaloric meal and snack foods differentially affect eating behavior. Appetite, 46(2), 117-123.

**Palmer, M. A., Capra, S., & Baines, S. K. (2011). To Snack or Not to Snack: What should we advise for weight management?. Nutrition & Dietetics, 68(1), 60-64.

***Buchholz, T. G. (2003). Burger, fries and lawyers: the beef behind obesity lawsuits. US Chamber of Commerce, US Chamber Institute for Legal Reform.