Nearly everyone wants to eat healthier. The food industry, which keeps a close eye on America’s changing tastes, has introduced thousands of foods that purport to be healthy — but are they really?

Too many people assume that anything that comes from a health-food store is good for you or that quantities don’t matter when you’re eating a “good” food.

Personal story: One of my first clients was a strict vegetarian, but this woman was 5’2″ and weighed 250 pounds. Something was clearly amiss. She told me that she used nearly a pint of olive oil in recipes because it’s a “healthy” fat.

Some foods, such as vegetables, whole grains, legumes, etc., are almost always good for you. But many of the foods that are promoted with healthy-sounding terms, such as “natural” or “vitamin-packed,” actually are loaded with sugar and/or fat and are unacceptably high in calories.

Common offenders — and healthier alternatives…

SMOOTHIES

Some smoothies can have more calories than sodas, making them an unhealthy choice to have regularly. My daughter once bought a peanut butter smoothie. I did the calculations and found that it had about 1,000 calories.

Healthier: Make your own smoothie using just fresh fruit and adding skim milk if you want. Or mix four ounces of fruit juice with four ounces of sparkling water. It tastes delicious, is relatively low in calories and has the same nutrients as a serving of whole fruit (though less fiber).

PROTEIN BARS

Millions of Americans replace one or more meals daily with bars — granola bars, high-protein bars, meal-replacement bars, etc. Many of these are high in sugar and/or fat and deliver 300 calories or more. It’s fine to occasionally use one of these bars as a meal replacement, but they’re too high in calories to have in addition to meals.

Healthier: Make up your own healthy snacks, using a mixture of nuts, seeds and dried fruit. One-half ounce of almonds (about 12) and one tablespoon of dried fruit totals about 140 calories. When you do crave a bar, have one that has at least three grams of fiber, with no more than 150 calories. Try Luna small-size organic bars.

FROZEN YOGURT

Healthier than ice cream? Not necessarily. Yogurt is one of the healthiest foods you can eat, but most frozen brands have more in common with desserts than with health foods. Check the label: Some frozen yogurts have the same number of calories as ice cream. They may even have similar amounts of sugar and fat. Also, it’s rare to find live and active cultures — the probiotic organisms that make natural yogurt so healthy — in frozen products.

Healthier: One of the newer versions of frozen yogurt. For example, Berry Chill, a yogurt chain based in Chicago, is producing products that are relatively low in fat and sugar and contain live and active cultures. Other manufacturers are following suit, such as New England–based Brigham’s with its premium frozen yogurt, élan. Look for the LAC seal on frozen yogurt containers — it means that the product has at least 10 million live and active cultures.

PRETZELS

They’re often touted as a healthier alternative to potato chips because they have less fat. A one-ounce pretzel serving usually has about one gram of fat, compared to up to 10 grams in a one-ounce serving of some potato chips. However, most pretzels are high in salt. They also have a high glycemic index because they consist mostly of refined wheat flour and cornstarch — they’re quickly transformed to sugar during digestion, which can increase blood glucose levels and lead to weight gain.

Be wary of pretzels with added wheat or oat bran — these often are just “window dressing” and not a significant source of whole grains.

Healthier: Satisfy your “crunch craving” with a mix of nuts, seeds and dried fruit.

FAKE WHOLE-WHEAT BREAD

Real whole-wheat bread is among the healthiest foods you can eat. Some brands, however, only look like whole wheat — manufacturers often add a brown color to make them look more wholesome. Another trick: Manufacturers super-size the slices so that they can make higher fiber claims on the label.

Healthier: A bread with normal-size slices that contains at least three grams of fiber per serving. Read the ingredient label. The word “whole” — whole wheat, whole grain, etc. — should be first in the list.

MUFFINS

Today’s big muffins often seem like they’re loaded with nutritious ingredients, such as fruit or bran, but many muffins that are sold in supermarkets or coffee shops, such as Starbucks, are loaded with fat and sugar and range from 400 to 500 calories each.

Healthier: A small one-and-a-half ounce muffin that’s made with bran or a whole grain. A muffin this size that’s not loaded with sugar and/or fat usually contains about 100 calories.

RICE MIXES

Brown rice has more fiber and disease-fighting phytochemicals than white rice, but people don’t always want to take the time to cook brown rice. Instead, they buy a packaged rice pilaf, both for convenience and extra flavor. Most of these products are very high in sodium, as well as fat.

Healthier: Uncle Ben’s microwavable brown rice. It’s ready in just a few minutes, and you can season it to your own taste — without adding salt or oil.