Unfortunately, there is such a thing as too much of a good thing. While healthy fats like avocados, trail mix, healthy oils and nut butters are nutrient-dense, they're also calorie-dense. "Even though they're healthy, the calories can add up -- and excess calories store as fat," Karena and Katrina say. "We don't count calories, but we like to stay calorie aware."

When it comes to healthy fats, stick to the serving size listed on your foods, otherwise those spoonfuls of peanut butter will add up quick, resulting in excess body fat.

Carbohydrates are a scary word for most women, and many are quick to cut carbs when they're trying to figure out how to lose body fat. While you should definitely be aware of the type of carbs you're scarfing down, Karena and Katrina say you shouldn't remove them from your diet altogether. "Carbs are vital, and they're how you burn fat," the Tone It Up duo says. "Remember in science class? 'Fat burns in a carbohydrate flame.' You just need to make sure you're incorporating the right carbs."

Karena and Katrina recommend replacing processed & packaged carbs (think: pasta, breads, breakfast cereals) with carbohydrates rich in fiber and nutrients, like sweet potatoes, quinoa, brown rice, whole-wheat wraps, brown rice wraps and oatmeal. These "good carbs" help to balance blood sugar levels, tone up muscle and shed body fat.

And we don't mean with a martini. "Hydration is key in keeping your metabolism high and your body functioning as a fat burning machine," Karena and Katrina say.

According to the fitness experts, dehydration causes fatigue, a slowed metabolism (yikes) and unhealthy cravings. The worst part? When you're dehydrated, your body can't burn fat efficiently, which means all of your hard work in the gym and the kitchen goes unnoticed.

"Make those workouts and healthy meals count by drinking plenty of water," Karena and Katrina say. "It's essential to drink at least half of your body weight in ounces daily." This means if you weigh 150 pounds, you're drinking 75 ounces of water throughout the day.

Yeah, yeah, we've all heard that breakfast is the most important meal of the day, but according to the Tone It Up duo, going for a run before you chow is an effective way to lose body fat fast. Ever heard of the term fasted cardio? It's a method regularly used by fitness competitors to get a jump-start on burning body fat -- and there's a reason they stick to it. "Exercising first thing in the morning -- before you've eaten -- is best for slimming your waistline," Karena and Katrina say. "When you wake up, your body is in a fasting state. If you work out before whipping up breakfast, it ups the level of fat oxidation." For those who don't speak fitness expert, this means burning fat for fuel.

For those who aren't familiar with high-intensity interval training (HIIT), this workout boosts the heart rate with quick, high-intensity bursts of exercise in between intervals of low-intensity activity (think: jogging with sprints). Why is this effective in losing body fat? Because it doesn't require hours of cardio (which wears and tears at the muscle, rather than building it) and confuses the body by getting it out of the steady state it goes into when you've been running on the treadmill for a half an hour. Instead, your body is forced to exert more energy, thus resulting in losing body fat.

"This is one of the most effective ways to burn fat," Karena and Katrina say. "It's usually a high-energy workout that includes intense cardio moves, which burns major calories." Incorporating even a 20-minute HIIT workout can be supereffective for those looking to lose body fat. Try this HIIT workout to torch your love handles.