Thursday, June 08, 2006

Re-thinking Calories - The Cost Per Ounce

In the June issue of the American Journal of Clinical Nutrition a study, Dietary energy density is associated with energy intake and weight status in US adults, researchers concluded "Adults consuming a low-energy-dense diet are likely to consume more food (by weight) but to have a lower energy intake than do those consuming a higher-energy-dense diet."

The researchers based energy density on foods eaten and did not include beverages in the calculation to avoid dilution - they explained their reasons with "Although several studies in the literature have found lower dietary energy density values to be associated with a more favorable body weight, other studies have not supported such a relation. One potential explanation for the inconsistent findings may be that different schemes for including beverages in the calculation of energy density were used in these studies. Beverages tend to have a lower energy density than do most foods and may disproportionately influence dietary energy density values."

In their discussion the researchers stated, "Although it is important to understand the relation between energy density and food intake, it is also critical to explore the relation between energy density and body weight. In the present study, those who were obese consumed diets higher in energy density than did those who were not obese."

Guess what? That was true!

However, a huge opportunity was missed in the discussion of the findings which clearly showed a strong association between non-water beverage consumption and obesity. You see, at the end of the day, those consuming diets with the lowest energy density and those consuming diets with the highest energy density - they both consumed similar total weight of food and beverages. Beverages clearly displaced food consumption and added more calories too!

The men eating a diet classed as "low energy density" consumed about 94.7-ounces total food and beverage a day; those in the middle range, about 94.6-ounces a day; and those in the "high energy density" group consumed about 93.1-ounces a day total. The women had similar eating patterns - those eating a diet classed as "low energy density" consumed about 69.5-ounces total a day; those in the mid-range, about 63-ounces a day; and those in the "high energy density" group ate about 64.9-ounces a day total.

Quite frankly the differences appear significant when we look at how much of that total is from beverages in each group! The weight from beverages for the men (from low to high energy density) was 49-ounces, 55-ounces and 61-ounces; for the women (from low to high energy density) the weight of the beverages was 36-ounces, 39-ounces and 42-ounces. As consumption of beverages (other than water) increased, so too did calories and the weight of food eaten. The beverages were providing weight and thus displacing food in the diets of these subjects!

Also noteworthy was the fact this study was designed to be a representative sample of US adults. The data clearly shows that the vast majority of people either cannot or will not reduce fat intake to below 30% of total calories - for whatever reason, a full 72% of those in the study ate a diet that provided 30% or more of their daily calories from fat.

Interestingly - and not discussed in the paper - is the prevalance of obesity was cut in half in those consuming a diet defined as "high fat" when fruit and vegetable intake exceeded nine-servings a day! You read that right - a 50% less chance of being obese when you eat nine or more servings of fruits and vegetables, even when you're consuming a diet that's considered "high fat."

In fact - regardless of dietary fat intake - there was no real difference between those eating a high-fat diet with less than 5-servings a day of fruits and vegetables and those that ate between 5-and-9 servings a day - the group that consumed the least, obesity affected 18% of the subjects, the group that ate 5-9-servings, obesity affected 17% of the subjects.

But, those that ate more than nine servings a day - just 9% were obese.

And what type of a diet do you eat if you're eating a diet that's "high fat" and rich with fruits and vegetables? You guessed it - one that is low-carb or controlled-carb! The reason is simple - you cannot eat excessive grains and added sugars if you're eating more than nine servings of fruits and vegetables a day!

Nine servings sounds like a lot, I know - but guess what? Even if you're following a low-carb diet, it's very easy to consume that much - five-to-nine-cups - in a day.

Want to see how easy?
  • 1/2-cup canteloupe, breakfast (1 serving)
  • 2-cups salad greens, lunch (1 serving)
  • 1-cup sliced cucumber, red cabbage, cherry tomatoes and shredded carrots (2 servings)
  • 1/2-cup blueberries, snack (1 serving)
  • 1-cup spinach, cooked, dinner (2 servings)
  • 1-cup mixed salad greens, dinner (1 serving)
  • 1/2-cup assorted salad fixings (cucumber, red cabbage, etc.) (1 serving)
  • 1/2-cup peppers and onions, dinner (1 serving)

Ten servings - 210 calories - 7-cups of fruits and vegetables - and just 30g net carbs!

Better still, the above provides almost 27-ounces of food by weight. If the average man consumes 94-ounces, the above just filled 28% of the total weight eaten in a day; if the average woman consumes 66-ounces a day, the above just filled 41% of the total weight eaten in a day.

Once you add proteins (meats, fish, poultry, eggs), some fats and an assortment of other good foods like nuts and seeds, there is little more you could eat if you tried - seven cups of fruits and vegetables is a large amount of food to eat in a day! Eating that much makes it difficult to overindulge in other, less nutritious food or consume large quantities of non-water beveages!

The data in this study clearly points to consuming fruits and vegetables as the best defense to protect against obesity. Regardless of fat intake - low-fat, high-fat - didn't matter, the overall rate of obesity was just 7.5% for those who consumed more than nine-servings of fruits and vegetables a day - half the 15.5% prevalance of obesity in those consuming nine or less servings a day!

That's right - in both the low-fat and high-fat groups, the prevalance of obesity doubled when fruit and vegetable consumption was at or less than nine servings a day!

What this tells me is that the foundation of eating well is fruits and vegetables - today, the vast majority of Americans eat less than five servings a day (and that's even if we include french fries, potato chips and fruit juice in the accounting)!

Our obesity epidemic isn't being driven because Americans are eating too much fat or not enough whole grains or too many animal foods - we're not eating enough fruits and vegetables (and I place stronger emphasis on vegetables) and that leaves us at risk of consuming excessive amounts of sugary beverages, processed foods, grains and junk food in general to provide us with the daily weight of food and beverages we're used to eating each day.

Remember, this study showed that overall consumption at the end of the day, by weight, was similar across all groups.

What differed was consumption of non-water beverages that provided for weight but added too many calories.

We have to get back to basics - and to put it simply, you get the most nutritional bang-for-the-calorie from non-starchy vegetables, followed by non-starchy root vegetables and fruits, followed by starchy vegetables.

We have to stop recommending people base their menus on a foundation of grains - these foods provide less nutrients and cost more calories to eat by the ounce because they have less moisture (water) packed in them.

A good example - a cup of cooked spinach has 57-calories and weighs 7-ounces. So, each ounce costs about 8-calories to eat. Compare that to a cup of cooked regular oatmeal (no fat added) - it weighs 8-ounces and has 145-calories in the serving, costing you 18-calories an ounce to eat.

Bottom line - we have to better communicate to the public not only the nutritional benefits of eating more fruits and vegetables, but also communicate the advantages in terms everyone seems focused on - calories.

But not just overall calories - let's begin to talk about the cost of calories per ounce....if we talk in these terms, who doesn't want to take advantage of the "savings" one gets when they eat fruits and vegetables?

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