Think you have bad genes for being healthy? Think again, says Dr Michael Roizen, cardiologist with the Cleveland Clinic and author of Real Age and You and You, Staying Young. Roizen, who spoke recently to a group of food writers in the US, believes that we ultimately can control our genes through making good choices. Those choices include choosing not to smoke, choosing to exercise, making good food choices and reducing stress.

"Genes depend on what you feed them - the stimuli," said Roizen. "Take diabetes. Ninty-nine per cent of type 2 diabetes is controllable with lifestyle changes. Smoking is another example. Smoking a pack of cigarettes a day shortens life span by eight years. But you can change that by stopping smoking."

Roizen believes most of us are programmed to have some type of cancer, but whether those cancer cells grow or not depends on the choices we make. His research found that diet and lifestyle can change gene expression for breast, prostate and colon cancers. The interventions include eating lower saturated and trans fats, adding whole grains, reducing the amount of processed foods, exercising 30 minutes a day and adding five minutes of meditation in the morning and evening.

At the Cleveland Clinic, he helped start an employee-wellness programme that made it easy for employees to choose healthy foods in the vending machines and cafeterias. He also offered a weekly Farmer's Market.

"The Farmer's Market changed employee's attitudes about healthy eating," said Roizen.

By the end of the employee programme, 40,000 employees had lost a total of 114,000 pounds in the first nine months, saving $19.6 million in health-related costs.

'Best by' and 'use by' dates

Question: Are the dates on food packages important for food safety or just suggestions for best quality?

Answer: These dates - 'best by', 'sell by' and 'use by' - mean different things and often are not required by federal law to be on the package. Most dates you see on food packages are not related to food safety; they tell you how long the product stays at peak quality. Those foods are safe and usable beyond those dates.

However, there are some important exceptions: Meat and poultry are labelled with 'sell-by' dates that are related to food safety. They should be cooked or frozen within two days after the sell-by date on the package.

Eggs may or may not have a 'sell-by' date, depending on state laws. Buy eggs before the date limit and use them within three to five weeks of purchase. As long as you store them properly - in their original carton and in the coldest part of the refrigerator (not the door) - even if the 'sell-by' date expires during that time, the eggs are quite safe.

Infant formula and many baby foods are required to carry 'use-by' dates, which reflect quality as well as nutrient retention. For example, if stored too long, formula can separate and clog the nipple. Don't buy or use baby formula or baby food after its 'use-by' date.

Of course, if foods are mishandled, bacteria can grow and cause food-borne illnesses regardless of the date on the package. For example, if cold cuts were left at room temperature more than two hours, they wouldn't be safe even if the date had not expired.

- American Institute for Cancer Research.

Charlyn Fargo is a registered dietitian at www.creators.com.