3. You burn more fat by exercising longer at a lower intensity – the myth of the ’fat-burning zone’.
No, we burn a higher percentage of fat as a fuel source when working at lower intensities, but we burn more total calories when exercising at higher intensities. At the end of the day, it’s calories in versus calories out that matters.

My doctor recommended I exercise at 60-70% my target HR, which would mean staying around 120-140 bpm, which seems rather low. She did refer it to the higher percentage of fat burned. Now if I exercise for 30 minutes at a time (cardio), would it make sense for me to exercise at this lower intensity, or to up it somewhere between 70-80%? I have a lot of weight I'd like to lose, so I don't mind (actually I think I'd like to) take it slowly, giving my body time to adjust as it happens.

She also recommended (as suggestions of course) doing cardio 4x/week, as well as weight training 4x/week, and eating 6 small meals a day. We went into more detail, but overall, that's the bigger picture.

What do you think? Any suggestions? I would really appreciate some input

your doctor sounds on the right track. I train at intervals myself, sometimes at 70% of heart rate, other times higher, as I'm trying to build my endurance, and lern to run, so I want to get used to working at a higher heart rate.

For a long time I worked at a lower intensity (my asthma gets unhappy when my heart rate goes up), and lost weight that way.

The six meal a day thing is a great idea, and a lot of people do that here, but I find it too difficult. I work in a call center with very strict breaks and can't manage even a tiny meal in a ten minute break without feeling like a horse at a trough!!!