营养/减肥/健康 FAQ

recipe · 发表于 2007-4-15 14:17:34

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注：这是一篇转贴，原文来自harvard nutrition FAQ (google harvard nutrition)
原文 http://www.hsph.harvard.edu/nutr ... html#healthyweight1

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小标题：

1: Healthy Weight
Q1: I am overweight. What is the best way to lose weight?
Q2: Is percentage of body fat important for health? Should I get my body fat
mea
sured at the gym?

2: Carbohydrates
Q3: I've been hearing the terms glycemic index and glycemic load. Are they
the s
ame thing or are they different?
Q4: Where can I get information about the glycemic index of foods?
Q5: Where do sugar free products or sugar substitutes like Nutrasweet fall
in th
e glycemic index and in the Healthy Eating Pyramid?
Q6: Is it true that a high carbohydrate diet is likely not advantageous to
weigh
t loss and weight control?

3: Fruits and Vegetables
Q7: Are organic fruits and vegetables better for you? How can you tell if
the fr
uits and vegetables were organically grown?
Q8: Is juicing fruit and vegetables a good way to get my nine servings a day?
Q9: I've heard that iceberg lettuce has limited nutritional value. Are some
vege
tables better than others?

4: Food Guide Pyramids
Q10:The Healthy Eating Pyramid looks a lot like the Mediterranean Food
Pyramid t
hat I have seen elsewhere. What are the differences?

5: Protein
Q11: Fish seems to be a good source of protein, but what do you think about
the recent concerns of mercury toxicity?
Q12: The Atkins diet plan says that it is fine to eat all the bacon, steak,
and butter I want for weight loss. Isn't that contrary to the advice that
the med
ical community is giving for a healthy heart?

6: Fat
Q13: My recent physical showed that my cholesterol is fine, but my
triglycerides are high. Is that something I need to worry about? Is that
something I can c
hange through my diet?

7: Fiber
Q14: Can you give me an idea of how many fruits, vegetables, and whole grain
products that I need to eat to get the recommended 20-35 grams of fiber
each day
?
Q15: I've heard that people experience a lot of gas and bloating when they
eat too much fiber. Is this true? How can I avoid it?

8: Calcium and Milk
Q16: I am sixty years old. My friend told me that I should stop drinking
milk because it will make my bones more brittle. Is that true?

9: Vitamins
Q17: What should I look for in purchasing a multivitamin? There are so many
kinds out there that I am completely confused.
Q18: I've heard from the health food store sales person that time release
vitamins are better for you. Does this make a difference in how the vitamin
is abso
rbed?

10: Alcohol
Q19: I heard that drinking alcohol is a risk for breast cancer in women and
yet there is much talk about the benefit of alcohol with heart disease.
Should I
still drink?
Q20: What is considered one serving of alcohol?
________________________________________________________________________

以上是所有的小标题，下面是每个问题的简要回答，以及长篇回答的LINK：

Healthy Weight
Q1: I am overweight. What is the best way to lose weight?
The optimal way to lose weight is to follow a lower calorie diet based on th
e Healthy Eating Pyramid food pattern and to incorporate daily physical acti
vity into your lifestyle. It is important to make small changes in your diet
and lifestyle rather than trying to go on a "crash" diet or "fad" diet clai
ming you can lose five pounds in one week. On average, you should aim for lo
sing half a pound to one pound each week. In addition, it is important to pa
y special attention to portion sizes. Average restaurant portion sizes are t
ypically two to three times the amount of food an average person needs in on
e meal. Furthermore, successful weight loss involves a permanent lifestyle c
hange; otherwise, you will easily regain the weight that you lost. If you ne
ed additional information or would like an individual consultation, ask your
primary care physician for a referral to a Registered Dietician.

For more information, please see Healthy Weight here:
http://www.hsph.harvard.edu/nutritionsource/healthy_weight.html
_________________________________

Q2: Is percentage of body fat important for health? Should I get my body fat
me
asured at the gym?
Your percentage body fat is important for your health. For an average person
, your Body Mass Index (BMI) can be a good measure of body fat. However, if
you are interested in the actual percentage of body fat, the gym may or may
not be the best avenue, depending on the method of body fat measurement and
the training of the personnel. Some methods for measuring body fat are bette
r than others. Skin calipers typically used in a gym are usually inaccurate,
since they are dependant on the skill of the person doing the analysis. Met
hods using bioelectrical impedance, such as a Tanita scale or a hand-held Om
ron body fat analyzer, are more accurate. The gold standard for body fat mea
surement is either underwater weighing or a full body DEXA scan, which is ve
ry expensive and usually reserved for research purposes. Also, remember that
although percent body fat is important, it is only a piece of the overall h
ealth picture.

For more information, please see Healthy Weight here.
http://www.hsph.harvard.edu/nutritionsource/healthy_weight.html
----------------------------------

Carbohydrates
Q3: I've been hearing the terms glycemic index and glycemic load. Are they
the same thing or are they different?

Glycemic index and glycemic load are two similar but different terms. Glyce
mic index indicates how rapidly a certain food increases blood sugar after e
ating, compared to the same amount of carbohydrate as white bread (50 grams
of carbohydrate). Glycemic load, on the other hand, takes into account the g
lycemic index of a food multiplied by the carbohydrate content of the food.
For most foods, the rule follows that a food with a high glycemic index will
also have a high glycemic load. However, there are exceptions to the rule;
carrots and watermelon have high glycemic index but a low glycemic load, due
to the small amounts of carbohydrate found in these foods.

For more information, please see Carbohydrates here:
http://www.hsph.harvard.edu/nutritionsource/carbohydrates.html
_____________________________________

Q4: Where can I get information about the glycemic index of foods?

More information about the glycemic index of foods can be found in the Carb
ohydrate section of this website, in Dr. Walter Willett's book Eat, Drink an
d Be Healthy, and on the University of Sydney's Glycemic Index website here:
http://www.glycemicindex.com/

_____________________________________

Q5: Where do sugar free products or sugar substitutes like Nutrasweet fall
in the glycemic index and in the Healthy Eating Pyramid?

Consuming foods made with Nutrasweet-especially beverages-are a better optio
n than consuming sugary drinks. Aspartame does not have a high glycemic inde
x, since it is not a carbohydrate. However, foods and beverages with sugar s
ubstitutes should be limited since the lifelong effects of these products ar
e unknown.

_____________________________________

Q6: Is it true that a high carbohydrate diet is likely not advantageous to
weight loss and weight control?

It is true that a high carbohydrate diet is likely not advantageous to weigh
t loss, and more importantly to long-term weight maintenance. This is becaus
e high carbohydrate diets also tend to be low in fat. In the past two decade
s, there has been a tremendous focus on low fat diets. In turn, food manufac
turers have produced low fat foods that are also high in refined carbohydrat
es and therefore tend to have a high glycemic index promoting more fat synth
esis and storage. In addition, it is important to realize that fat is an imp
ortant component of a meal. Fat helps to make you feel fuller more quickly,
as well as add flavor to meals. Furthermore, plant oils also contain "health
y" fats rich in monounsaturated and polyunsaturated fats.

For more information, please see Fats and Cholesterol and Healthy Weight
below:
http://www.hsph.harvard.edu/nutritionsource/fats.html
http://www.hsph.harvard.edu/nutritionsource/healthy_weight.html

______________________________________

Fruits and Vegetables
Q7: Are organic fruits and vegetables better for you? How can you tell if t
he fruits and vegetables were organically grown?

Organic fruits and vegetables will limit your exposure to pesticides. Howeve
r, organic produce tends to be much pricier than conventional produce, and m
ay not be any more nutritious than conventional fruits and vegetables. To ge
t a better dollar value for organic fruits and vegetables, try growing your
own, finding a cooperative, or buying from a local farmer. New food labeling
guidelines required by the U.S. Department of Agriculture will help you det
ermine if a fruit or vegetable was grown organically.

For more information, please see Fruits and Vegetables here:
http://www.hsph.harvard.edu/nutritionsource/fruits.html

_______________________________________

Q8 : Is juicing fruit and vegetables a good way to get my nine servings a d
ay?

Juicing can help meet the nine servings per day. However, it is best to eat
your fruits and vegetables in their "whole" forms since juicing separate the
fruit juice from the fruit pulp, which contains most of the fiber that may
be beneficial for your health. Also, juicing fruits will increase the glycem
ic index of the food since the fruit sugars are more readily available.

For more information, please see Fruits and Vegetables.
http://www.hsph.harvard.edu/nutritionsource/fruits.html

_______________________________________

Q9: I've heard that iceberg lettuce has limited nutritional value. Are some
vegetables better than others?

You've heard correctly. Iceberg lettuce has very little nutritional value; i
t is mostly water and a small amount of fiber. Vegetables that are better fo
r you tend to be richer in color. For example, compare iceberg lettuce to sp
inach; spinach is better for you since it is rich in iron and folate. Compar
e white potato to sweet potato; sweet potato is better for you since it is r
ich in beta carotene and other vitamins.

For more information, please see Fruits and Vegetables.
http://www.hsph.harvard.edu/nutritionsource/fruits.html

______________________________________

Food Guide Pyramid
Q10: The Healthy Eating Pyramid looks a lot like the Mediterranean Food Pyr
amid that I have seen elsewhere. What are the differences?

There are a lot of similarities between the Healthy Eating Pyramid and the M
editerranean Food Pyramid. However, the Mediterranean Food Pyramid is repres
entative of a traditional diet followed by many people in Mediterranean coun
tries such as Greece and Italy. The Healthy Eating Pyramid is based on the m
ost up-to-date research in nutrition and health.
Some specific differences between the two pyramids include potato being at t
he bottom of the Mediterranean Food Pyramid, compared to at the top of the H
ealthy Eating Pyramid (in the "use sparingly" category). Also, the Healthy E
ating Pyramid emphasizes plant sources of protein and whole grains. In addit
ion, plant oils, such as olive oils, arte at the bottom of the Healthy Eatin
g Pyramid, whereas they are in the middle of the Mediterranean Food Pyramid.
In addition, the Healthy Eating Pyramid recommends daily physical activity
and a multivitamin supplement for most individuals.

For more information, please see Food Pyramids here:
http://www.hsph.harvard.edu/nutritionsource/pyramids.html
___________________________________

Protein
Q11: Fish seems to be a good source of protein, but what do you think about
the recent concerns of mercury toxicity?

Fish is a good option for a protein source since it is low in fat and high i
n omega-3 fatty acids. Research suggests that eating just 6 oz per week of f
atty fish, such as salmon or sardines, may be enough to reduce the risk of d
ying from heart disease by 36 percent and reduce the overall risk of death b
y 17 percent. This makes fish perhaps one of the healthiest foods that you c
an eat. Although there has been some recent concern about contaminants in fi
sh such as mercury and PCBs, the evidence suggests that the proven health be
nefit of fish consumption is much greater than the potential for harm among
individuals who consume fish 1-2 times per week. However, for women who are
or may become pregnant, women who are nursing, and young children, mercury t
oxicity may be a concern for some types of fish. It is best to eat a variety
of fish. Women who are or may become pregnant, women who are nursing, and y
oung children should avoid shark, swordfish, king mackerel and tilefish; ins
tead, they should eat two serving a week of a variety of other fish and seaf
ood, such as salmon, shrimp, chunk light tuna, or scallops. (For additional
information, see the FDA/EPA dietary advice statement(link below) on mercury
in fish and shellfish.) People who eat fish five or more times a week
should also limit consumption of fish high in mercury.

http://www.cfsan.fda.gov/%7Edms/admehg3.html
______________________________________

Q12: The Atkins diet plan says that it is fine to eat all the bacon, steak
and b
utter I want for weight loss. Isn't that contrary to the advice that the med
ical community is giving for a healthy heart?

The Atkins diet plan's recommendations for weight loss are contrary to the m
edical community's advice. This type of diet is very high in unhealthy satur
ated fat and cholesterol(http://www.hsph.harvard.edu/nutritionsource/fats.html), which may be harmful to your heart in the long run. In addition, the Atkins diet is also high in red meat and processed meats, which have been linked to colon cancer.

For more information, please see Protein here:
http://www.hsph.harvard.edu/nutritionsource/protein.html
_______________________________________

Fat
Q13: My recent physical showed that my cholesterol is fine, but my
triglycerides are high. Is that something I need to worry about? Is that
something I can c
hange through my diet?

High triglycerides can be of concern to your health. Interestingly, a lower
fat diet will not likely lower your triglyceride levels. However, a diet low
er in carbohydrates, in particular, high glycemic index carbohydrates such a
s sugar, white potato, white breads and white pasta should help. In addition
, an increase in monounsaturated fats, such as olive oil, may be beneficial.

For more information, please see Fats and Cholesterol here:
http://www.hsph.harvard.edu/nutritionsource/fats.html

_______________________________________

Fiber
Q14: Can you give me an idea of how many fruits, vegetables, and whole grain
products that I need to eat to get the recommended 20-35 grams of fiber
each day
?

You can easily achieve 30 grams of fiber each day by eating 3 servings of fr
uit, 3 servings of vegetables, 2 servings of whole grain foods, and 1 servin
g of legumes, such as lentils, kidney, black and lima beans. To achieve 35 g
rams of fiber, eat 4 servings of fruit, 4 servings of vegetables, 4 servings
of whole grain foods, and 1 serving of legumes.
Note on serving sizes: One serving of fruit is one whole, medium-sized fruit
or

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