Today's gung-ho enthusiasm for getting healthy in the new year may not last. But the latest science tells us that even short bursts of effort matter.
Small changes that you stick with can yield big results. Even if you backslide, some benefits can remain.
• Get in a good workout, and days later your body still is doing a better job of regulating blood sugar.
• It's discouraging to lose a few pounds and then put them back on again. But experts say such weight cycling generally is not harmful. Plus, you may have improved your health during the time you weighed less.
• Heavy drinkers who stop can repair much of the damage to their livers — provided they take charge before an irreversible condition such as cirrhosis has set in.
• Quitting smoking is famously tough. But scientists say to keep trying; the benefits of kicking the habit are major, and they start within hours of taking your last puff.
Whatever your resolutions, make sure they are well-chosen and not too extreme. Modest adjustments, practiced repeatedly, become habit more easily than radical change. And if you overdo a health kick, you actually can hurt yourself.
So if you're thinking that starting on New Year's Day you will all at once quit smoking, quit drinking, run 5 miles a day and lose 50 pounds on a macrobiotic diet, it's time to get real.
"Nothing in excess," advised Barbara Hansen, a professor at the University of South Florida and director of its Obesity, Diabetes and Aging Research Center. "It's trite."
When calories count
Lost in the constant chatter about losing weight is how much science doesn't know about the long-term effects of dieting. Individual factors like age, genetics and body type determine your ideal weight — a number that has little to do with those skinny jeans you dream of wearing.
"There's not a nice, easy formula to apply," Hansen said.
Consider a Swedish study of 2,000 obese people who underwent bariatric surgery to lose weight.
Fifteen years later, many of the study participants are still overweight or obese — though less severely than when they started. But they are reporting fewer cases of diabetes and hypertension, said Claude Bouchard, chair in nutrition and genetics at the Pennington Biomedical Research Center in Louisiana. He is involved in the Swedish study.
But what about a person who is not obese (defined as a body mass index over 30), but just 10 or 20 pounds overweight? Is dieting a health imperative at that size?
"It's very hard to tell whether it's advantageous for an overweight person to lose weight or not," said Bouchard. Since the risks of excess weight rise as the pounds increase, it's clearer that an obese person does benefit from weight loss.
While many will regain weight over time, most researchers no longer consider weight cycling — also known as yo-yo dieting — harmful, even if the benefits are limited, Hansen said.
"The longer you keep it off, the better," she added.
By losing weight and keeping it off, she noted, you can postpone or control Type 2 diabetes, improve your cholesterol and reduce your risk of deadly heart attack and stroke.
But the USF professor cautioned that too-rapid weight loss can be detrimental, especially in the elderly. That's because when large quantities of weight are lost quickly, significant amounts of lean muscle are lost along with fat. And if the weight is regained, it's likely to come back in the form of fat. So ultimately, you're less healthy than when you started.
Baby steps to exercise
Don't consider it a failure if you can't stick with a New Year's resolution to exercise daily.
And don't think your workout isn't working until you see sleeker thighs and bigger biceps. Inside, your body is reaping benefits from the start.
Even a few times a week of modest exercise is worth your time, according to the Pennington Center's Bouchard.
"The glass is not full, but it is only half empty," he said of limited exercise. "A little bit helps, and more is better — and a great deal is even better. But we've got to begin to walk before we run, and that applies to changing your behavior as well."
With regular exercise, he noted, your body improves its ability to regulate blood sugar. The benefits linger for days after your last workout, but are largely gone if you don't exercise again for a full week.
Exercise has similar impact on blood pressure and cholesterol, Bouchard said, although it's not clear how long these benefits last.
Relief from depression, insomnia and anxiety also are benefits of modest exercise you may enjoy from the start.
The main danger in exercise is pushing to the point of injury. In the elderly, a misstep that leads to a fall can break a joint such as a hip, a devastating event. On the other hand, seniors who stay active, particularly with yoga and tai chi, are less prone to balance problems.
Even younger athletes can land in the emergency room with life-altering sprains, strains and tears if they overdo a health kick.
So if you're new to exercise, start with walking. For more, seek advice from a trainer at your local gym or senior center.
Drinkers: Less is more
Some studies show that moderate drinking can reduce the risk of heart disease and stroke and even help people with Type 2 diabetes. (And by moderate, scientists mean one drink per day for women and two for men.)
But a recent study found that women who have as few as three drinks a week can see a small increase in their breast cancer risk.
Such contradictions are one reason researchers generally don't suggest that nondrinkers pick up a cocktail solely for health benefits. And it's never wise to drink if you are pregnant, taking medications that could react with alcohol or have a family history of alcoholism.
What is clear are the harmful effects of excessive drinking. Over years, alcohol can harm almost every organ, from the liver to the heart, which can become enlarged, and the brain, impairing memory and decisionmaking ability.
Yet even heavy drinkers can improve their health by scaling back — if they do it in time.
"It depends when you quit and after how long," said Sam Zakhari, director of the Division of Metabolism and Health Effects at the National Institute on Alcohol Abuse and Alcoholism.
If you haven't been diagnosed with a serious problem, such as cirrhosis or brain damage, he said, it's probably not too late.
"If you quit before you inflict irreversible damage, then you are fine," he added. "The liver can regenerate and the muscle can be strong again."
Job One: Quit smoking
If you do nothing else for your health in the new year, quit smoking.
"It really represents the most important health behavior change that an individual can make to impact their health," said Vani Simmons, a researcher in the tobacco research and intervention program at Moffitt Cancer Center in Tampa.
That applies even to patients who have already developed tobacco-related cancers. Treatment can be more effective, with fewer side effects, in patients who quit, Simmons said. And breaking the habit can prevent a new cancer from developing.
"Some patients — maybe even some (health care) providers — might say once somebody has got cancer, what's the point'' in quitting, Simmons said. "There still is a point."
Don't throw up your hands if you've failed before. It often takes a half dozen or more attempts for a smoker to successfully break the habit. And think of it this way: Any time you spend not smoking is an improvement.
"You can't quit quitting," Simmons said. "It's pretty clear-cut."
Letitia Stein can be reached at email@example.com or (727) 893-8330.