Your exercise routine is probably burning far fewer calories than you think. I’ve been doing some experimenting with my heart rate monitor recently and here are the somewhat disappointing numbers:

1 hour of hot yoga: 170 calories

25 minutes of trail running (during which I felt like I might die at any moment): 237 calories

1 hour of tennis practice: 200 calories

40 minutes of open ocean swimming: 300 calories

If you want to get a major calorie burn on you really have to put in some time, which is not realistic for most people.

7 hour day hike: 1200 calories

2 ½ hours of running (13.1 miles, half marathon): 1300 calories

Even if you had the time, putting workouts like these in every day would be a very quick way to an injury and long recovery.

What’s my point in telling you this? It’s certainly NOT that exercise has no value. When it comes to your health, a minimum of 30 minutes a day is a wonder drug, as this video explains. Even when it comes to weight and fat loss, a consistent exercise program can help keep you on track and will reshape your body.

But if your goal is weight loss, you have to look at what you are eating. A burger and fries can easily counter your 7 hour day hike. Rewarding yourself with dessert because you are working out will lead you nowhere. If you want to change your body, you need to change your food choices as well as your activities.

The first step is to keep a food journal. Record EVERYTHING that you eat or drink for at least a week. It’s a very enlightening process, I assure you. Just becoming more aware of what you’re eating can make a big impact. After the week, evaluate your journal and choose 2-4 things to work on for the next week. Making dietary changes in small increments instead of huge cuts will help ensure that you stick with your program, rather than binge after a week or two of strict adherence.

Have you ever kept a food journal? How did it affect your eating?