One plus one equals?

The answer’s not always as obvious as you might think.

“A day without sunshine is like, you know, night.” That Steve Martin quote might seem obvious, but the humor comes from the fact that, honestly, we just hadn’t thought of it that way!

What is obvious but not funny is the difficulty folks have seeing the connection between certain health problems and serious complications that threaten quality of life and even life itself.

Three recent studies made us think about how hard it is sometimes to connect the dots and then take action to upgrade your lifestyle and health. So here are some important causes and effects that you’ll want to learn about and act on, so you can thrive.

>> One: Being overweight is directly linked to heart disease.

>> Plus One: 70 percent of Americans are overweight or obese.

>> Equals: Half of adult Americans have cardiovascular disease.

But a new study from the Cleveland Clinic shows that while many folks (88 percent) have heard that being overweight and heart disease are related, 40 percent of those who describe themselves as overweight or obese say they aren’t careful about which foods they eat.

The study researchers, led by Dr. Steven Nissen, also highlight other health- damaging beliefs and misinformation:

>> Fully 46 percent believe artificial sweeteners help you lose weight, when studies show they don’t help.

>> Most Americans don’t know that obesity is linked to elevated lousy LDL cholesterol levels or coronary artery disease, and 64 percent don’t know it can lead to a stroke.

Your takeaway:

If you’re gaining weight or are overweight or obese, you have great power to chart a new history for your family and become heart healthier. The first step is to give up the Five Food Felons: red and processed meats, added sugars and syrups, and any grain that isn’t 100 percent whole. Then move aerobically for at least 30 minutes, five days a week and do strength training twice a week

>> One: Type 2 diabetes or prediabetes affects more than 100 million Americans.

>> Plus One: About 20 percent of adults with Type 2 diabetes — 7.2 million Americans — don’t know they have it. Only 11.6 percent of adults with prediabetes know they have it.

>> Equals: Around one-third of the U.S. population is at risk for serious complications related to prediabetes or diabetes.

Prediabetes increases your risk of heart disease, and diabetes is linked to many complications, including nerve and kidney disease, sexual dysfunction and depression. Now, according to research published in JCI Insight, there’s another complication from diabetes: Chronically elevated blood glucose promotes loss of muscle mass.

Your takeaway:

Lack of physical activity is a huge contributor to the development of diabetes-related complications. Research shows that as you age, if you build instead of lose muscle mass, you live longer! So start a walking group and get out for 30-60 minutes five times a week. Work out using hand weights or stretchy bands at least twice a week for 30 minutes.

>> One: Forty-five million Americans go on a diet every year. But two-thirds of weight lost is generally regained within a year. About 75 million Americans have high blood pressure, but less than half of them have it under control.

>> Plus One: Frequent fluctuations in weight and blood pressure (as well as glucose and LDL cholesterol) cause stress on all of your systems and promote inflammation.

>> Equals: A study in Circulation found that those with the greatest ups and downs in weight were 53 percent more likely to die of heart disease, and those with the greatest fluctuations in blood pressure were 19 percent more likely to die of cardio complications.

Your takeaway:

Before you develop heart disease, adopt a healthy diet and regular exercise routine — and stick with it. If you’re diagnosed with those conditions, stick with medications and lifestyle changes. Your goal: Walking 10,000 steps a day this year; keep it up next year. Give up red meat this year; make it a lifetime commitment.

Mehmet Oz, M.D., is host of “The Dr. Oz Show,” and Mike Roizen, M.D., is Chief Wellness Officer and Chair of Wellness Institute at Cleveland Clinic. Email questions to youdocsdaily@sharecare.com.