Popular belief says if you really want to make a big change, focus on one new healthy habit at a time. But Stanford University School of Medicine researchers say working on your diet and fitness simultaneously may put the odds of reaching both goals more in your favor. They followed four groups of people: The first zoned in on their diets before adding exercise months later, the second did the opposite, the third focused on both at once, and the last made no changes. Those who doubled up were most likely to work out 150 minutes a week and get up to nine servings of fruits and veggies daily while keeping their calories from saturated fat at 10 percent or less of their total intake. 

The tiny gender differences in minerals other than calcium and iron depend on body size. But while the dietary requirements for selenium fit this rule, men may benefit from supplements of about 200 micrograms a day, a level about four times above the RDA. That's because both a clinical trial and an observational study suggest that selenium may reduce the risk of prostate cancer. It's far from proven, but it's something for men to consider.
To help you learn how to eat healthfully, start with the U.S. Department of Agriculture's (USDA) dietary guidelines system, which you can find at http://www.mypyramid.gov. The MyPyramid system, which looks somewhat like the familiar food pyramid of old, offers guidance based on individual needs and replaces "serving" recommendations with actual amounts of food. It also emphasizes the importance of balancing nutritious (and tasty!) food choices from all food groups every day with daily physical activity.
Research has consistently shown that the elliptical, although easiest on joints, is worse than the treadmill, stationary bicycle, and rowing machine (not to mention activities such as swimming and intense hiking) when it comes to elevating heart rate and burning body fat. This is due to the fact that movement on these machines relies heavily on momentum and not resistance or the propelling of one's bodyweight. All these months of elliptical training has yielded mediocre results, and now you know why.

The U.S. Department of Agriculture's (USDA) food pyramid system (www.mypyramid.gov) provides a good start by recommending that the bulk of your diet come from the grain group—this includes bread, cereal, rice and pasta— the vegetable group; and the fruit group. Select smaller amounts of foods from the milk group and the meat and beans group. Eat few—if any—foods that are high in fat and sugars and low in nutrients. The amount of food you should consume depends on your sex, age and level of activity.

There's not much doubt about this one: Women need more iron than men, because they lose iron with each menstrual period. After menopause, of course, the gap closes. The RDA of iron for premenopausal women is 18 mg a day, for men 8 mg. Men should avoid excess iron. In the presence of an abnormal gene, it can lead to harmful deposits in various organs (hemochromatosis). Since red meat is the richest dietary source of iron, it's just as well that men don't need to wolf down lots of saturated fat to get a lot of iron.
The recommended daily intake for vitamin E is 15 mg. Don't take more than 1,000 mg of alpha-tocopherol per day. This amount is equivalent to approximately 1,500 IU of "d-alpha-tocopherol," sometimes labeled as "natural source" vitamin E, or 1,100 IU of "dl-alpha-tocopherol," a synthetic form of vitamin E. Consuming more than this could increase your risk of bleeding because vitamin E can act as an anticoagulant (blood thinner).