Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Vegetarianism wikipedia , lookup
Overeaters Anonymous wikipedia , lookup
Food safety wikipedia , lookup
Gluten-free diet wikipedia , lookup
Human nutrition wikipedia , lookup
Obesity and the environment wikipedia , lookup
Diet-induced obesity model wikipedia , lookup
Food studies wikipedia , lookup
Food coloring wikipedia , lookup
Raw feeding wikipedia , lookup
Food politics wikipedia , lookup
Tamara Truax AGEC 352 Term Project December 7, 2007 Effects of Food Group Serving Standards on a Minimum Cost Diet I created a low cost diet by evaluating 20 different foods based on price and 10 nutrition constraints. The nutrition constraints were based on a 2000 calorie diet as recommended for a young female adult with average physical activity. The minimum cost diet of the twenty foods came to $1.20 per day. This diet contained only 4 foods none of which were fruits or vegetables. The USDA recommends a balanced diet to include foods from all five food groups whereas my minimum cost diet only included food from three food groups. I added five additional constraints forcing the model to use a minimum number of foods from each of the five food groups. This second diet was of course more costly than the first at $2.85 per day. The nutrition standards given cover many constraints however they do not require the diet to be diverse in the five food groups. I was interested to see whether the minimum cost diet would include foods from the five different food groups automatically or whether these constraints would have to be added to the model. Growing up we have always heard to eat our fruits and vegetables, but the question is can we get the nutrients and vitamins we need without eating fruits and vegetables. If we can how much more will the diet cost to follow the additional recommendations from the USDA on daily servings of the five food groups. To create my model I choose twenty foods from our class list. When choosing the foods, I tried to keep an even amount of breads and grains; fruits; vegetables; meat, eggs, and nuts; and dairy. I knew the minimum cost diet might not include all of these categories, but when I added the food group constraints I wanted the model to have more than one choice to use from the different food groups. When adding the additional food group constraints, I used the old USDA food group serving standards. This added five additional constraints to my model. The new USDA standards are in weight instead of servings. I was unable to use these new standards because the weight of the servings was not included in the data, but I spoke to a dietician who told me the old and new standards should be pretty close to one another. The USDA translated them into weight to avoid the confusion of defining what a serving size is for each different food. I gave each of the foods an objective value of 0, 1, or 2 for the food group serving constraints. For example the jr. cheeseburger has 2 servings of grains because it has two slices of bread. It also has 1 serving of dairy, 1 serving of meat, and 0 servings of fruits and vegetables. For the right hand side of these constraints, I used the minimum daily serving recommendation for each food group. My minimum cost 2000 calorie diet used four foods and cost $1.20 per day. This diet included 6.19 servings of peanut butter, 5.49 servings of multi-grain flakes, .78 servings of long grain rice, and .34 servings of 2 percent milk. The calorie, sodium, fiber and calcium constraints were all binding. The sensitivity report shows the most expensive foods which could be included into the diet would be raisins, oats, and Wendy’s broccoli and cheese potato. Fiber is the most expensive binding constraint. Each additional unit of fiber costs about $.013. Calcium is the next most expensive; then calories and sodium. I find it interesting you can obtain all the recommended vitamins without having to eat the recommended number of servings from the different food groups. I think this is possible because some foods are enriched or fortified with vitamins they would not normally have. This diet is also very high in fat with 874.59 grams. This is mainly due to the 6 servings of peanut butter which each contain 140 grams of fat. I am curious if requiring minimum servings from each of the food groups will lower the fat content, mainly due to increased intake of fruits and vegetables. I expect the use of peanut butter to lower, however peanut butter is important for the binding constraints: fiber and sodium. Looking over the possible candidates for fruits and vegetables, the lowest reduced cost on the sensitivity report would include green beans and pineapple. However this does not take into account some of the other foods which contain servings from more than one food group such as Campbell’s vegetable beef soup. The minimum cost diet with the additional food group constraints came to $2.85 per day; $1.65 more than the first solution. This diet included pineapple and green beans in addition to the multi-grain flakes, rice, milk, and peanut butter. The servings of multi-grain flakes increased from 5.49 to 6.28. Rice increased 2 servings making the final value 2.78. The usage of milk also increased from a third of a serving to 2 servings. Peanut butter decreased about 68% coming to 2 servings. The diet included 3 servings of green beans and 2 servings of pineapple to fulfill the fruit and vegetable constraints. The decrease in the servings of peanut butter decreased the amount of fat in the diet by 66%. The fat content was originally 874.59 grams and in the second solution it was 300.45 grams. In the second solution the sodium and calcium constraints are no longer binding. This is largely because of the amount of sodium in the green beans and the increased servings of milk which has the most calcium. Of the new constraints the vegetables; fruits; meat, eggs, and nuts; and dairy constraints are all binding. The fruit constraint costs the most with a shadow price of $0.32. Next most expensive are the vegetable and dairy constraints at $0.25 and $0.22 respectively. The meat, eggs, and nuts are the least expensive food group constraint at $0.02. The shadow price of the calorie constraint decreased to $0.0001. While the cost of fiber in the new diet increased from $0.01 to $0.03. Looking at the allowable price increases, they are fairly high for milk, peanut butter, and pineapple. For milk this is probably because there is not really another good dairy source on the food list. It would be interesting to see if the price of the diet would change if cheese or yogurt were added to the food list. The multi-grain flakes have an allowable increase of $0.01. This means a one cent increase in the price would affect the usage of the multi-grain flakes. Rice also has a low allowable increase of $0.02. If the prices of these two foods went up it would probably dramatically change the diet. In conclusion, all of our nutritional needs can be met without eating food from each of the five food groups. However, including all five of the food groups helped to lower the fat intake of the diet. A diet including food from all five food groups also had less binding constraints on nutrients. At the same time, a minimum cost diet with all five food groups would cost approximately $1040 per year; $602 more than the minimum cost diet without the food group constraints. In the end the question is whether the lower fat content, larger variety, and increased vitamins is worth the increased cost of a diet which meets the food group standards.