When you're time-crunched and starving, pre-packaged foods may seem like a tempting solution. But according to experts, these speedy snacks often come with a high price. Some are loaded with so much sodium that they could send your blood pressure sky high, while others are packed with preservatives, artificial flavorings, and empty calories. Here, seven convenience foods you should avoid at all costs—and their healthier alternatives.

1. Lunchables

 In addition to being virtually devoid of nutrients, Oscar Mayer's popular pre-packaged kids' lunches are chockfull of fat and salt. The Ham and Cheddar Cracker Stackers variety boasts a whopping 20 grams of fat and 930 milligrams of sodium, roughly 60 and 40 percent of the recommended dietary allowances (RDA), respectively.

Healthy Substitute: A low-sodium ham-and-cheddar sandwich on whole-grain bread takes only a few minutes to prepare but can make a world of difference for your child's health. Add lettuce and tomato for an extra nutritional punch.

2. Bright Orange Snack Foods

As a general rule of thumb, if it's an almost-electric neon hue that never appears in nature, you're better off not eating it. The orange coloring found in many packaged snack foods, such as cheese puffs, mac and cheese, and vending-machine cheese-and-cracker packs, is brimming with sodium and preservatives.

Healthy Substitute: Stick to carrots, oranges, or sweet potatoes to get your color fix. Trust us, your waistline and blood pressure will thank you. If it's cheese you need, go for soy singles instead. American cheese soy slices come individually wrapped, too, and have less than a third of the calories and about half the sodium of the singles you ate growing up.

3. Frozen Pizza

Pizza often gets a bad rap, and those of the frozen variety don't help its reputation. Conventional frozen pizzas are loaded with sodium and fat-laden meats and cheeses, not to mention superthick crusts that add on hundreds of calories per slice.

Healthy Substitute: Choose brands with fiber-rich whole-wheat crust, zero trans fat, and soy or veggie toppings. Or for a safer substitution, do it yourself: Split a whole-wheat or multigrain English muffin or pita, top each side with a low-calorie sauce and part-skim mozzarella cheese, then either microwave or bake in the oven.

4. Toaster Pastries

You can enjoy them hot or cold, but either way, you might as well be eating a pastry from your favorite bakery. Two Kellogg's Frosted Strawberry Pop-Tarts contain 400 calories and 34 grams of sugar, more than a Krispy Kreme glazed raspberry-filled doughnut.

Healthy Substitute: Cut open a whole-wheat English muffin, and top with strawberry preserves for a quick breakfast with half the sugar and calories. Better yet, eat a cup of whole strawberries topped with a few tablespoons of Cool Whip. You'll still get your sugar fix, but mostly from the strawberries; Cool Whip has only 1 gram of sugar and 25 calories per serving.

5. Hot Dogs

Who doesn't know by now that hot dogs are a hot mess? In fact, any type of meat preserved with nitrates (which includes sausages, bacon, and canned ham) should prompt you to proceed with caution, as several studies have shown that high consumption of nitrates may increase the risk of certain cancers and even chronic obstructive pulmonary disorder (COPD).

Healthy Substitute: If you just can't give up this convenience food, soy dogs are the healthiest option. In addition, there are an increasing number of nitrate-free meats on the market, including some products sold by Hormel and Boar's Head.

6. Smoothies

You may think they're healthy, but check the nutritional information before you reach for one of these blended beverages. One mango Jamba Juice smoothie contains 440 calories and roughly 90 grams of sugar—more than double the amount that can be found in a Three Musketeers bar. Even worse is the peanut butter "smoothie" (really, a milkshake in disguise): It has an outrageous 840 calories and 21 grams of fat.

Healthy Substitute: Choose the light versions, which have about half the calories and sugar. Or try blending low-calorie fruit yogurt, soy or skim milk, and frozen berries for a less frightening version of this refreshing treat. You could also stick to unsweetened plain yogurt with a drop of honey and a handful of real fruit.

7. Ramen Noodles

Who knew that these noodles could be such a health nightmare? An infamous staple for college students and budget-conscious adults, Ramen noodles are crammed with salt, with one beef-flavored packet yielding close to 400 calories and almost 1,600 milligrams of sodium.

Healthy Substitute: If a soup craving hits, a safer bet is a low-sodium version of your favorite store variety. Or cook the Ramen, but toss the little seasoning packet. Instead, saute a few of your favorite vegetables (try red peppers, onions, and broccoli) and some mushrooms. Toss with the noodles, and you have a much healthier meal.