Cheryl Forberg, RD. Biggest Loser Nutritionist

What is important to note is that in hot weather your body is prone to dehydration and this actually can have an affect on your metabolism. In the course of an average day, sweating, breathing, and waste elimination together leach more than 10 cups of water out of your body -- and that's without exercise. If you don't replace what you've lost, you may become dehydrated; your system literally begins to dry out.

Dehydration lowers your body's energy levels, too. Because blood is mostly water, when you're dehydrated the volume of your blood diminishes, lowering amounts of oxygen and nutrients that reach your tissues. Recent studies show there's a trickle-down effect on metabolism: Dehydration slows your system to such an extent that you burn fewer calories than you would otherwise during the course of the day. And dehydration can cause other undesirable symptoms, including headache, dizziness, muscle weakness, and a dry, sticky mouth.

Some people say that their appetite decreases when it’s hot outside. If that’s the case, you should still try to eat small frequent healthy meals throughout the day. Many people find cool gazpacho refreshing in hotter weather. Try my easy recipe for Icy Gazpacho with Fresh Lime.

The take away here: When it’s hot outside, drink plenty of water, and don’t skip your workout!

When it’s super hot outside, try not to exercise during the hottest part of the day, especially if you’re exercising out doors. Early morning and evenings are your best bets. To make sure your body does not overheat, monitor your heart rate. Some people invest in a simple heart rate monitor.  It’s also important to don the appropriate workout attire. Don’t wear sweats or heavy clothes while working out when it’s hot. Sweating more doesn’t help you burn more calories; it just may dehydrate you more. And most important, as I mentioned, stay hydrated!

So how will you take advantage of the summer heat and make it work for you?