NEW YORK -- Every day we make decisions about what to eat and what to drink, but it often seems what's good for us one day, is not the next. That's because research hasn't always been clear.
"In the late 1970s, people were being told to avoid eggs," said Dr. Walter Willett, a researcher at Harvard University. "A little bit later, to avoid all fat if you actually could, but there was actually no evidence or data supporting that."
Now, more precise and long-term research is steadily revealing that the little decisions we make actually carry a lot of weight.
In a new study, researchers at Harvard followed more than 40,000 men over 22 years and found those consuming just one 12-ounce sugar-sweetened drink a day increased their chance of having a heart attack by 20 percent. Two sugary drinks: a 42 percent increase. Three a day: 69 percent.
"It does cause a spike in blood sugar and it causes a big burst of insulin," Willet said. "If we do that day after day, they're hanging around. It's not just a spike for a few hours."
The American Beverage Association disagrees, and in response to the study said, "drinking sweetened beverages does not cause an increased risk of heart disease." Adding that these findings "could have been the result of other lifestyle changes."
Another study, looking at red meat consumption over 28 years, found men and women who ate a serving a day were 13 percent more likely to die prematurely.
The National Cattlemen's Beef Association says no one food has "been shown to affect mortality" and "the scientific evidence to support the role of lean beef in a healthy, balanced diet is strong."
As the results from many long term studies accumulate, what defines a healthy diet is becoming ever more clear. Experts suggest nuts, poultry and fish as sources of protein, eating fewer refined carbs, and staying away from saturated and trans-fats, going for good fats instead.
The real question is, do people have the will power to make those healthy choices?