Every week, we’re bringing you a roundup of the latest health and wellness news to hit the wire. This week, we look at why more than a week of keto might not be beneficial, why energy drinks are especially bad for heart health, and why one number might help explain the obesity epidemic in this country.

Quick bouts of keto better than a keto lifestyle?

New research conducted by Yale University found that a ketogenic diet in mice produces health benefits in the short term but negative effects after about a week.

The study, published in Nature Metabolism, indicates that consuming a high-fat, low-carb diet (99 percent protein and fat and 1 percent carbohydrates) could over limited time periods reduce diabetes risk and inflammation, according to YaleNews. It’s the first step toward clinical trials of the diet in humans and provides real insight into the mechanisms at work in the body on the keto diet.

Researchers found that the positive and negative effects of the diet were both linked to tissue-protective immune cells called gamma delta T cells, which fight inflammation and lower diabetes risk.

When dieters eliminate most carbohydrates, the body acts as if it’s in a starvation state and begins burning fat instead of carbohydrates, yielding chemicals called ketone bodies as an alternate source of fuel. When the body burns ketone bodies, researchers said, these gamma delta T cells expand throughout the body.

After a week on a keto diet, mice had lower blood sugar levels and inflammation. But when the body is in this “starving, not starving” state, fat storage is happening simultaneously with fat breakdown, the researchers found. When the rodents continued to eat the diet beyond one week, they began to lose the T cells and began to consume more fat than they could burn, developing diabetes and obesity.

Long-term clinical studies in humans are needed, researchers said, to determine whether such a diet is safe enough to be prescribed for those who are overweight and pre-diabetic.

Put down the Red Bull, energy drinks are worse than soda

Energy drinks, with their high-caffeine content, may give you that jump-start, but they appear to have a more negative effect on people’s hearts and blood pressure than other caffeinated beverages, such as coffee or soda, according to a small study published in the Journal of the American Heart Association, covered by Time.

In the study, 19 men and women were given either a typical 32-ounce energy drink with 320 milligrams of caffeine, as well as taurine and ginseng, or a soda-like control drink that contained the same amount of caffeine with a bit of lime juice and cherry syrup. After six days, the groups switched and drank the other beverage.

Researchers measured everyone’s blood pressure at the start of the study, as well as one, two, four, six and 24 hours after drinking the beverages. Heart activity also was measured with an electrocardiogram.

Those who drank the energy drink had a QT interval—or the time it takes the heart ventricles to prepare to beat again—that was 10 milliseconds higher than those who drank the sodas. Irregularity of these intervals can lead to abnormal heartbeats. Indeed, medications that affect the QT interval more than 6 milliseconds carry warning labels.

Both groups had higher blood pressure after their drinks, though not out of normal range. But while the blood pressure of the soda group returned to normal after six hours, in those who drank the energy drink, it remained elevated, which leads scientists to believe it’s not the caffeine but the other ingredients responsible for this prolonged effect.

The findings suggest that people should approach energy drinks with caution, particularly those with risk factors for heart issues. And those with cardiac disease or hypertension should avoid them.

If you made it to the gym today …

Feel good about it. While your resolutions may be flagging, you’re doing better than a significant part of the population. A new joint study from the Centers for Disease Control and Prevention in The Washington Post has found that more than 15 percent of the American adult population in every state gets no physical activity at all during their leisure time. That’s right, no running, walking, gardening or golf.

The most inactive was Mississippi, with 33 percent of its adult population labeled as inactive, a trend among southern states. The state with the fewest was Colorado at 17.3 percent. You can see how your state fared here.

Photo credit: LauriPatterson, Getty Images