But hidden in between the burgers and tacos are some "healthy" options: salads, grilled chicken, yogurts, oatmeal, power burritos.

Doesn't sound too bad, right?

I spent a week eating nothing but these "healthy" fast foods and I lost six-and-a-half pounds.

But even though I lost about a pound a day, it didn't really go well.

I live in New York City, a place with every possible food you could want.

Eating healthy here, it's a breeze.

But across America, there are more than 200,000 fast food joints, and they're bringing in more than $200 billion a year in sales.

And no matter where you go, you're never far from a place like McDonald's or Taco Bell.

But in recent years, consumers want better, healthier choices, and the traditional fast food places have been losing customers to those fast casual healthy options.

The rules were pretty simple.

Eat every major meal at a national fast food chain and stick to the healthy options.

McDonald's, Wendy's, Burger King, Taco Bell, Dunkin' Donuts, Subway, and Chick-fil-A; nothing but them for a week.

Yeah, I lost almost seven pounds, but let's take a close look at the numbers.

On a normal day, I'm eating around 2,500 calories.

An adult man should be having about 2,400 to 2,600 calories a day.

But on this fast food plan, my calories plummeted.

Most of these meals came in under 400 calories, and that was one of my first problems.

I'd eat and just a couple hours later, I was starving.

And I had days when I didn't eat more than 1,000 calories.

Now, some of these meals were really good.

My favorite was this grilled chicken market salad from Chick-fil-A.

It had blueberries, strawberries, apples; it was delicious and it was actually healthy.

However, a lot of the other salads from Burger King, McDonald's, and Wendy's were loaded with salt, often more than 50% of what I needed for the entire day, from a salad.

In fact, excess salt was a problem the entire week.

I thought I had hit the jackpot with Taco Bell's al Fresco menu.

They take off all the cheese and mayo-based sauces and replace it with lettuce and pico de gallo.

One night I got tacos, another night I got a power cantina burrito, and these were meals with more protein than usual.

So, I felt like I was getting enough food.

They were good, too good.

It was all salt.

In fact, just one burrito had almost as much salt as I needed in just one day.

The American Heart Association says we should limit our sodium to about 2,300 milligrams a day, but the ideal is closer to 1,500 milligrams a day, especially for a person like me with high blood pressure.

But if you look at my sodium intake, it was high every day.

Yet I was barely getting the calories I needed.

If I wanted to keep the sodium down, I was starving.

If I wanted to feel full, salt through the roof.

You see, that's an issue in the fast food industry.

Wendy's even acknowledges on their website that there's going to be a trade-off between salt and flavor.

It was weird.

I didn't feel healthy at all throughout the week, even though I was eating healthy foods and losing weight.

And on the last day, I had this massive headache that was just infuriating.

These places, they're supposed to be tasty, cheap, and convenient.

But it wasn't cheap.

Every healthy option was expensive, but left me hungry.

For eight grilled nuggets and this tiny kale salad at Chick-fil-A, $12.

For the power Mediterranean salad at Wendy's, it was almost $8.

Yet I could get a cheeseburger, nuggets, fries, and a soda for only $4.

That brings me to another problem.

Walk into McDonald's and you get hit with that sweet, sweet french fry smell, and I had to get a salad.

Would I recommend this to anyone?

Nope, unless you're stuck on the road with no other options.

Though there was a bright spot: breakfast at Subway.

They have these egg-white-and-cheese sandwiches, which I got covered in spinach and peppers.

And let me tell you, it was good.

But after all this, I just want a cheeseburger.