When my younger brother died at age 23, it soon became clear that I had never learned how to grieve.

I was in my twenties, too, but that important life lesson had escaped me. For a time, my waking moments were consumed by a single thought: “What do I do now?”

How to grieve a tragedy like the death of someone close to us, maybe a pet — any significant loss really — isn’t taught in schools. It’s not a class you can sign up for, but it’s vitally important to your mental and spiritual health.

Few emotions can have more power over us than grief. Left unattended, it can deaden the senses and depress the spirit.

If you’re obese or overweight, grief might well have contributed to the way your body looks today. Many people are emotional eaters and I can understand why. Eating something delicious improves your mood. Food can become your best friend when your feelings are numb, offering comfort — like having someone put their arm around you.

Food doesn’t talk back or say no. It doesn’t judge. No police officer ever ordered you to put down a doughnut.

Drugs and alcohol work in a similar way, numbing the pain of our grief like food offers comfort. The cop might care about the drugs and alcohol, but we can use and abuse at home without anyone watching.

Considering all the destructive and unhealthy responses we’ve invented to cope with our grief, I can confidently say that fitness saved my life.

In a way I was lucky. I was never a big eater, and using alcohol and drugs to numb my grief never crossed my mind. The one thing I knew in my 20s — and knew well — was how to exercise. Over time I found that going to the gym made me feel better. So when I wasn’t indulging my anger toward God, I let out my emotions at the gym.

At the time my brother died I was working as an aerobics instructor. The same group of people attended my class often enough that we all grew fairly close. In those early days I would actually spend time in the middle of class crying and talking about my brother.

As I clocked valuable hours on the job, I would pour out my emotions right then and there. That was how I grieved.

My boss eventually caught wind and put a stop to my ad-hoc grief circle. That’s when I realized something I wish I’d learned much earlier: I wasn’t the only one at the gym holding onto grief. Everyone in class had some emotional problem of their own to work out, and it wasn’t fair to add my stress to theirs.

My boss was right; sharing the pain over losing my brother in class wasn’t the right time or place.

And yet, it really helped.

The solution to coping with grief is all around us — people, not food. The mind and spirit cannot flourish on their own. Neuroscience tells us that the emotional reaction to rejection derives from the same part of the brain that responds to physical pain. It’s no wonder that 20% of Americans identified loneliness as a source of suffering in one survey. A broken heart can hurt just as much as a broken bone! We’re hard-wired to be connected and when we’re disconnected, it’s painful.

That’s why making deep, lasting connections with other human beings is just as essential to your health as any diet or exercise plan. Having friends means you’re less likely to turn to food for comfort in times of stress, as studies show a high correlation between obesity and loneliness.

Having no one to grieve with means no one to tell you when you’re not taking good care of yourself — and no one to tell you to put down that doughnut.

If you’re addicted to food, drugs or alcohol, and you don’t know why, search your soul. Have you learned how to grieve? It’s never too late to start sharing your story.

Theresa Roemer is a health and fitness expert, entrepreneur and author of the recent book “NAKED in 30 Days: A One Month Guide to Getting Your Body, Mind and Spirit in Shape.”