Choose a diet low in fat
Fat, whether from plant or animal sources, contains more than
twice the number of calories of an equal amount of carbohydrate
or protein. Choose a diet that provides no more than 30 percent
of total calories from fat. The upper limit on the grams of fat
in your diet will depend on the calories you need . Cutting back
on fat can help you consume fewer calories. For example, at 2,000
calories per day, the suggested upper limit of calories from fat
is about 600 calories. Sixty-five grams of fat contribute about
600 calories (65 grams of fat x 9 calories per gram = about 600
calories). On the Nutrition Facts Label, 65 grams of fat is the
Daily Value for a 2,000-calorie intake
The notion that you could lose weight by cutting out carbohydrates
and eating plenty of protein was once tut-tutted by the medical
establishment partly because such diets were based on little more
than interesting ideas and speculation. In the past two years,
head-to-head trials that pitted high-protein, low-carbohydrate
diets against low-fat, high-carbohydrate diets have given them
a scientific leg to stand on. These trials show that high-protein,
low-carbohydrate diets may work more quickly than low-fat diets,
at least in the first six months. After a year or so, though,
weight loss is about equal. Compared with a low-fat, high-carbohydrate
diet, a higher-protein diet that goes easy on saturated and trans
fats may decrease the amount of triglycerides in the blood, which
is also good for the heart.
Can you get too much protein? Digesting it releases acids that
the body usually neutralizes with calcium and other buffering
agents in the blood. Eating lots of protein, such as the amounts
recommended in the so-called low-carb or no-carb diets, takes
lots of calcium. Some of this may be pulled from bone. Following
a high-protein diet for a few weeks probably won't have much effect
on bone strength. Doing it for a long time, though, could weaken
bone. In the Nurses' Health Study, for example, women who ate
more than 95 grams of protein a day were 20 percent more likely
to have broken a wrist over a 12-year period when compared to
those who ate an average amount of protein (less than 68 grams
a day).(1) Although more research is clearly needed to define
the optimal amount of daily protein, these results suggest that
long-term high-protein diets should be used with caution, if at
all.
All protein isn't alike
Some of the protein you eat contains all the amino acids needed
to build new proteins. This kind is called complete protein. Animal
sources of protein tend to be complete. Other protein sources
lack one or more amino acids that the body can't make from scratch
or create by modifying another amino acid. Called incomplete proteins,
these usually come from fruits, vegetables, grains, and nuts.
Vegetarians need to be aware of this. To get all the amino acids
needed to make new protein - and thus to keep the body's systems
in good shape - people who don't eat meat, fish, poultry, eggs,
or dairy products should eat a variety of protein-containing foods
each day.
