Here is a fantastic article on nutrition trends that one of the mods posted on H&F over on MAP. Really a worthwhile read. This was lifted from:

http://wholehealthsource.blogspot.com/2008/12/us-weight-lifestyle-and-diet-trends.html

For this post, I compiled statistics on U.S. weight, health and lifestyle trends, and graphed them as consistently as possible. They span the period from 1970 to 2007, during which the obesity rate doubled. The data come from the National Health and Nutrition Examination Survey (NHANES), the Behavioral Risk Factor Surveillance System (BRFSS), and the U.S. Department of Agriculture (USDA). Some of the graphs are incomplete, either because the data don't exist, or because I wasn't able to find them.
http://4.bp.blogspot.com/_zULJExxrW54/SUX2Ms0CGBI/AAAAAAAAAVg/9TgAdvZkECA/s320/Data+1.jpg
Obesity is defined as a body mass index (BMI) of 30+; overweight is a BMI of 25+. Yes, it's frightening. It has affected adults and children (NHANES).
http://2.bp.blogspot.com/_zULJExxrW54/SUX2HkWwfrI/AAAAAAAAAVY/nuL2kEGY-aA/s320/Data+2.jpg
The percentage of Americans who report exercising in their spare time has actually increased since 1988 (BRFSS).
http://2.bp.blogspot.com/_zULJExxrW54/SUX2BKAeLAI/AAAAAAAAAVQ/3ullx0b51ws/s320/Data+3.jpg
We're eating about 250 more calories per day, according to NHANES.
http://1.bp.blogspot.com/_zULJExxrW54/SUX156GandI/AAAAAAAAAVI/eaVW0e3ZY7w/s320/Data+4.jpg
The 250 extra calories are coming from carbohydrate (NHANES).

http://4.bp.blogspot.com/_zULJExxrW54/SUX1zBfc1sI/AAAAAAAAAVA/qC6rqiuxf98/s320/Data+5.jpg
We're eating more vegetables and fruit (USDA).
http://4.bp.blogspot.com/_zULJExxrW54/SUX1rKvA52I/AAAAAAAAAU4/GzJvdf-Hkk8/s320/Data+6.jpg
We're eating more meat by weight, although calories from meat have probably gone down because the meat has gotten leaner (USDA). This graph represents red meat, fish and poultry. The increase comes mostly from poultry. Boneless, skinless chicken breasts anyone?
http://2.bp.blogspot.com/_zULJExxrW54/SUX1mI56_9I/AAAAAAAAAUw/GwcWI6QIi1A/s320/Data+7.jpg
We're eating more sugar (USDA). The scale of the graph doesn't allow you to fully appreciate that sweetener consumption had increased by a full 100 calories per day by 1999, although it has dropped a bit since then. This is based on food disappearance data. In other words, the amount consumed is estimated using the amount sold domestically, minus a percentage that approximates waste. High-fructose corn syrup has seized nearly 50% of the sweetener market since 1970.
http://2.bp.blogspot.com/_zULJExxrW54/SUX1eayFd0I/AAAAAAAAAUo/SMvZnOXUNBs/s320/Data+8.jpg
Again, the scale of the graph doesn't allow you to fully appreciate the magnitude of the change here. In 2000, we ate approximately 2.5 ounces, or 280 calories, more processed grains per day than in 1970 (USDA). That has since decreased slightly (34 calories). You might be saying to yourself right now "hey, that plus the 100 calories from sugar adds up to more of an increase than the NHANES data show!" Yes, and I think that points to the fact that the data sets are not directly comparable. NHANES data are self-reported whereas USDA data are collected from vendors. Regardless of the absolute numbers, our processed grain consumption has gone way up since 1970.

Wheat is still king. Although we grow a lot of corn in this country, most of it gets fed to animals. We prefer eating wheat without first feeding it to an intermediary. In absolute quantity, wheat consumption has increased more than any other grain (not including corn syrup).
http://3.bp.blogspot.com/_zULJExxrW54/SUX1ZpPZ-6I/AAAAAAAAAUg/Ht7S6mzMXG8/s320/Data+9.jpg
Bye bye whole milk. Hello skim milk (USDA).

http://1.bp.blogspot.com/_zULJExxrW54/SUX1VDExRbI/AAAAAAAAAUY/VbRKmOHvPGQ/s320/Data+10.jpg
This graph represents "added fats", as opposed to fats that occur naturally in meat or milk (the USDA does not track the latter). Added fats include salad oil, cooking oil, deep fry oil, butter, lard, tallow, etc. We are eating a lot more vegetable oil than we were in 1970. It comes chiefly from the industrial, omega-6 rich oils such as soybean, corn and canola. Added animal fats have increased slightly, but it's pretty insignificant in terms of calories.

There is an artifact in this graph that I have to point out. In 2000, the USDA changed the way it gathered vegetable oil data. This led to an abrupt, apparent increase in its consumption that is obvious on the graph. So it's difficult to make any quantitative conclusions, but I think it's clear nevertheless that vegetable oil intake has increased considerably.

Between 1970 and 1980, something changed in the U.S. that caused a massive increase in obesity and other health problems. Some combination of factors reached a critical mass that our metabolism could no longer tolerate. The three biggest changes in the American diet since 1970:

An increase in cereal grain consumption, particularly wheat.
An increase in sweetener consumption
The replacement of meat and milk fat with industrial vegetable oils, with total fat intake remaining the same.Mainstream America has done to itself what it did to native American and other indigenous cultures worldwide, with the same result.




Source: http://wholehealthsource.blogspot.com/2008/12/us-weight-lifestyle-and-diet-trends.html

Some pretty interesting statistics, it's pretty interesting to see how the usual dietary culprits of saturated fats, dairy and lack of fruit and veg have had very little impact on rising rates of obesity, whereas 'health' foods such as cereals, vegetable oils and low fat dairy have all increased.

That is an interesting article, thanks. Do you know of anywhere I can go for a fuller analysis of the conclusions, though, as to my amateur eye it seems that many of the nutritional changes described would be generally considered healthier, whereas the un-fleshed out implication is that they have somehow combined to promote nationwide obesity.

Am I being really stupid, but what am I missing here? I get that we're eating more calories overall, but we're also exercising more, eating more fruit and vegetables, drinking skim milk and eating leaner meats - virtually all of the dietary orthodoxies I have slavishly followed myself over the last 20 years.

Is there another chart for fat people that shows a dramatic rise in cake intake? Is it really all the fault of wheat?

A few alternate conclusions.

While the number of people reporting exercising in their spare time has increased the data makes no mention of what is being used as a definition for exercise, duration or intensity.

While the calorie count hasn't risen sharply the simple truth of calories in > calories out = fat must be observed. The graph states that ~2700 is average in America. Most people need roughly 2000. This disparity could account for the weight gain. Add to this the reduction in strenuous physical activity and/or long duration physical activity present in a predominantly industrial and agrarian society.

While "healthy" foods are on the rise you must also consider portion size, as well as the average Americans complete inability to estimate calorie consumption. Most restaurant meals tip the scales at 800-1200 calories per plate. Add in desert and a few glasses of soda and you have consumed close to your daily allowance in one meal.

I would be curious to see studies done on the change in portion sizes, as well as the McDonaldization of American cuisine.

^^^Plus other stuff I have seen suggests that it's really about a split. We have half of america eating better and getting more "fitness" exercise (although they are still more sedentary due to desk jobs etc) but the other half eating much worse.

Some pretty interesting statistics, it's pretty interesting to see how the usual dietary culprits of saturated fats, dairy and lack of fruit and veg have had very little impact on rising rates of obesity, whereas 'health' foods such as cereals, vegetable oils and low fat dairy have all increased.

Wait, this data, when looked at as a whole, makes me look far less like a fringe lunatic than the conventional wisdom tends to indicate. Same goes for this guy, after whom I model my diet http://high-fat-nutrition.blogspot.com/

Note: Because I'm so very much more physically active than the blogger, I aim to get more protein to my muscles, so I shoot for 60-70% of my calories from saturated fats, compared to his goal of 80. Also with little to no glutens and enough carbs to stay out of ketosis (which is why this is totally different from Atkins).