Friday, July 29, 2011

What You See, Part 4

Part 4 (from this article):   On average, study participants gained a pound a year, which added up to 20 pounds in 20 years. Some gained much more, about four pounds a year, while a few managed to stay the same or even lose weight.  Participants who were overweight at the study’s start tended to gain the most weight, which seriously raised their risk of obesity-related diseases, Dr. Hu said.
This is an interesting finding.  It would be curious to study their diet questionnaires to see what the common factors are in their diets.  What I suspect may be true is that either:
-They were fatter because they already ate too many carbs for too long, and/or:
-They continued the pattern of eating that led to their initial weight gain, but as their body began to mal-adapt to the excessive carbohydrate intake, they gained weight even faster.
A third possibility is that this population is a group that had the most insulin sensitive fat cells, which could continue to respond to insulin and absorb excess carbohydrate as sequestered fat.
The foods that contributed to the greatest weight gain were not surprising. French fries led the list: Increased consumption of this food alone was linked to an average weight gain of 3.4 pounds in each four-year period. Other important contributors were potato chips (1.7 pounds), sugar-sweetened drinks (1 pound), red meats and processed meats (0.95 and 0.93 pound, respectively), other forms of potatoes (0.57 pound), sweets and desserts (0.41 pound), refined grains (0.39 pound), other fried foods (0.32 pound), 100-percent fruit juice (0.31 pound) and butter (0.3 pound).
This part of Ms. Brody’s reporting is pure fantasy.  All they could report is which foods correlated with the greatest weight gain.  They may have had high paid statisticians who assumed some numbers and attempted to determine causality – but to believe that such a thing could actually be done is to believe in voodoo and chicken bones.  These are great statistical equivalents of card tricks, and can be a heck of a lot of fun, but they do not and cannot determine what caused what.  What’s far more significant is what happens when well designed intervention studies are completed – and these studies consistently show a benefit for carb restriction with moderate protein intake and a high percentage of daily calories from fat consumption.
Also not too surprising were most of the foods that resulted in weight loss or no gain when consumed in greater amounts during the study: fruits, vegetables and whole grains. Compared with those who gained the most weight, participants in the Nurses’ Health Study who lost weight consumed 3.1 more servings of vegetables each day.
This is interesting, but it is meaningless to try and convert co-relation – people who lost weight ate 3 times as many vegetables – with causality; “people who eat more vegetables will lose weight.”    Part 5 tomorrow.

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