Bodies Haven't Changed...Why Do Diets?

Like many companies today, mine has a wellness initiative.  As part of the initiative, we receive various kinds of information about diet, exercise, smoking, and other behaviors affecting health.  Today, we had a "lunch and learn" about diet and wellness.

Our wellness consultant, who was on the phone, gave a PowerPoint presentation about insulin and blood sugar.  Basically, she said that carbohydrates only stay in the body for a short time, so we feel hungry soon afterwards and our blood sugar spikes more than with fats or proteins.  She talked about the "white devils" that include wheat, sugar, rice, and pasta.  She said that a breakfast of bacon and eggs cooked in butter with a side of berries is better than cereal and skim milk with orange juice.  She sang the praises of the Paleo diet while denouncing doing too much cardio, and declared that the best exercise was circuit training.

Basically, she dissed everything that I do and advocated everything that I do not like.

I realize that high-protein diets are very popular, as is weight bearing exercise.  Crossfit and meat are in, while running and pasta are out.  The thing is, I am old enough to remember when the opposite was advocated-stay away from fat, and chow down on pasta and rice.  Before that, my parents were told to eat cottage cheese and steak to lose weight.  Bodies haven't changed, so why does the optimal diet seem to change each generation?  It's similar to the conventional wisdom about babies-nowadays they must be put on their backs or they will choke on their own spit-up, whereas when my daughter was little it was practically infanticide not to place them on their bellies.  But I digress.

I don't pretend to understand all of the details about how the human body works.  When our wellness consultant showed us her slide depicting all of the fat cells in the liver spilling out of what appeared to be a funnel, I sort of got the idea but I found it a bit hard to grasp completely.  However, I do know what works for me.  I practically live on carbs-I always have.    I've never been a fan of fatty foods, meat, or dairy.  Furthermore, although I lift weights and do Bikram Yoga (not as cardio intensive as some), running is my first exercise love.

There has always been some controversy and confusion about diet and exercise.  I honestly don't think that anybody has the one true answer.  I do know that, in American society at least, people keep getting fatter and more sedentary.  Maybe the same things don't work for everyone.  I do know what works for me.  Therefore, when a wellness consultant tells me how I should eat and exercise, I will listen, smile politely, possibly take some of the advice, and leave what I know doesn't work for me.