I’ve been hearing for some time now that when it comes to losing weight, exercise isn’t king. Diet is paramount. I mean, the NY Times said it, so it must be true.1 To be fair, they cited a lot of reputable studies in their report that seem to indicate that exercise only goes so far in weight management. The amount you can burn in a single exercise session is easily erased by something as innocent as a second helping at dinner or a favorite candy. Also for many, hunger increases after exercise and leads to overeating, erasing or even worsening the calorie deficit they were struggling with. I get it. I can see how exercise may not be the key piece in the giant weight loss puzzle.

That said, I’ve always had a nagging suspicion that exercise is more important than we think. We already know that it helps for a number of issues other than weight loss, including mood/depression, cardiovascular health/blood pressure, blood glucose regulation, hormonal balance, improved immune function, etc. People who exercise are generally healthier. Period. But I still had a feeling that, given the right duration and intensity level, exercise plays a key role in weight management.

Then this study appeared online2 and gave us a new perspective on what might be going on with our metabolism when we exercise.

Researchers at the Karolinska Institute in Sweden found mechanisms in mice by which exercise counteracted fat storage and decreased inflammation. A compound called kynurenic acid, induced through exercise, was the key.

To get the big picture, back up with me real quick. Before this study, in 2014, this same group originally published that kynurenic acid in the brain, produced through exercise, improved brain function. Exercise produces a healthy mind, they declared.

On that basis, they did this recent study in which they introduced kynurenic acid orally into mice with the goal of reaching all tissues, not just the brain. These mice, while consuming a high-fat diet that promoted obesity and raised blood glucose, stopped gaining weight and, in turn, converted more of their white fat to brown fat, which is the type that is metabolically more active. They also had improved blood glucose control despite not having changed their diet.

The theory is that kynurenic acid in fat cells promoted this white-to-brown fat conversion, while kynurenic acid in immune cells enhanced anti-inflammatory properties.

These two factors, increasing metabolically active fat and decreasing inflammation, help the body’s ability to burn fat for energy and prevent excess fat storage.

It sounds promising! Lace up those shoes! But then this begs the question, what kind of exercise should we be doing to get this benefit? What is the magic formula? Run? Light walk? Pilates? HIIT cardio? CrossFit? Yoga?

Unfortunately, this study does not establish that, as the kynurenic acid was administered orally rather than directly induced through exercise. However, a little research and another article provided exactly that information: resistance exercise.3

Oh, I knew it! She had a suspicion that the timing and intensity of the exercise mattered. Quick and dirty workouts have their place, but nothing replaces a good workout to get your heart rate up for a sustained period of time.

What this study showed was that subjects subjected to sustained cardiovascular exercise, in these cases for an hour or more, produced high levels of kynurenic acid in muscle tissue one hour after exercise. Subjects doing exercise that involved shorter bursts of intense energy did not see these benefits.

there you go Cardio for the win, right? Well, yeah, mostly I guess. I think the key takeaway is to remember that cardio is important and has an important role in weight management, but don’t let that make you overlook the role of muscle conditioning, toning, and even plyometric-type activities in weight management. strength and general health. Varying your routine to prevent injuries and strengthen your body in general is also very important!

If you are now wondering what type of exercise is safe for you, let me post a brief disclaimer here. I am not an exercise physiologist. I work with food to help people lose weight, however exercise is a key piece of that puzzle. I’ve also been an avid athlete since I was in my 20s, so I tend to talk about it frequently with my clients. That said, if you need specific advice on what’s safe and appropriate for you, consult with your doctor, a physical therapist, or even a certified trainer to develop a plan. My role is to educate that exercise is important. For personalized guidance, especially if you have injuries or other limitations, consult a professional!*

If you feel up to starting something on your own, let me post a quick add-on to one of my favorite online training websites, Fitness Blender.com. For accessible, achievable, and FUN workouts, this site is the best. Run by a local Seattle couple, they have FREE online workouts for any fitness level and any time frame you have available. I will be honest. We don’t always have time for sustained cardio, do we? These workouts can easily fit into your day, whether you have 15 minutes to spare or an hour.

However, the truth is that if you really want to lose that weight for good, regular exercise should be part of your routine.

So yes, lace up your shoes and get moving because the evidence is clear: exercise, and specifically cardio, supports fat reduction. Of course, you should also watch your diet.

*Always check with your doctor before beginning any new type of exercise program. If you decide to try something new, always start slow and always be mindful of proper form. If in doubt, consult a coach or teacher to master the fundamentals before increasing intensity. Basically start low and slow to avoid injury!