I’ve been hearing for some time 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 many authoritative studies in their report that seem to indicate that exercise only goes so far in weight control. 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 sweet. Also for many, hunger increases after exercise and leads to binge consumption, erasing or even worsening the calorie deficit they were striving for. I understand. I can see how exercise may not be the key piece in the giant weight loss puzzle.

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

Then this study came online2 and gave us a new perspective on what might be happening to our metabolism when we exercise.

Researchers at the Karolinska Institutet 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 understand the big picture, backtrack with me real quick. Prior to 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 where 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 asset. They also had improved blood glucose control despite not having changed their diet.

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

These two factors, increased metabolically active fat and decreased inflammation, aid the body’s ability to burn fat for energy and prevent excessive 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 kynurenic acid was administered orally rather than directly induced through exercise. However, a bit of research and another article provided exactly that information: resistance exercise.3

Oh, I knew it! She had a suspicion that the time 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 undergoing 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 strength and general health. Varying your routine to prevent injuries and strengthen your body in general is also very important!

If you are now thinking about what type of exercise is safe for you, please allow me to post a short 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 sportsman 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 plugin for one of my favorite online workout 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’ll 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 forever, regular exercise should be part of your routine.

So yeah, lace up your shoes and get moving because the evidence is clear: exercise, and specifically cardio, supports fat reduction. Of course, you should also take care of 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 trainer or teacher to master the fundamentals before increasing the intensity. Basically start low and slow to avoid injury!