Just because a food claims to be “diet” food doesn’t really mean it’s true.  Food’s that claim to be low-calorie, light or fat-free are not all they claim to be. Despite the label, these foods can actually do more harm than good from a weight-loss, health perspective.  Here is why.

100-calorie snack packs:

The idea behind these is to provide a pre-portioned snack that is good for snacking and stops you from eating a large bag of snack food to the bottom. This is not a bad idea as long as you stop at one small pack. Unfortunately, that rarely happens.  On top of that, these snacks tend to be highly processed made up of white flour, sugar, and 100 calories of unsatisfying food.  They also lack any kind of appetite-suppressing nutrients such as fibre, protein, and healthy fats, which means you will be hungry again in a few minutes.

Instead:

Eat 100 calories of the following: 3 dried apricots and 3 walnut halves; 1/3 cup of yogurt and 1/2 cup of berries;

15 grapes and 1/2 ounce of cheese.

Light Peanut Butter:

Fat-reduced peanut butter is not really unhealthy (unless they add sugar to enhance the flavour) but what’s the point.  The fat-reduced peanut butter only saves you 10 calories and 2 grams of fat.  One of the big problems is that it reduces the consumption of a healthy fat that helps to improve blood vessel function and benefits blood-sugar control.

Instead:

Stick with regular peanut butter and practice portion control.  Better yet, choose a natural peanut butter.

Diet pop:

Some research has shown that artificially sweetened drinks is actually linked to weight gain over time.  The thought is that by providing a sweet taste, artificial sweeteners may impair the body’s ability to gauge caloric intake resulting in eating more and more calories and particularly craving more sweet foods.

Instead:

Switch to water (sparkling or still) and add a splash or fruit juice or real fruit to add a bit of flavour.

Fat-free salad dressing:

One of the healthy aspects of salad dressing is the healthy fat. Healthy oils such as olive, grapeseed, sunflower, canola, or walnut, adds flavour, texture, and nutrients including vitamin E and omega-3 fats.  It helps your body absorb fat-soluble vitamins and antioxidants from greens and other vegetables.  Instead these dressing tend to be made with water, thickeners, preservatives, and sugar.  Using a fat-free or “light” dressing may result in using more dressing to off-set the lack of flavour.

Instead:

If you buy commercial salad dressing go for full-fat versions that are made from the above healthy fats. Drizzle

your salad with about 2 tablespoons.

Fat-free cheese slices:

Although these cheeses provide only 25 calories per serving, you are also consuming unhealthy additives such as corn starch, salt, binders, natural and artificial flavours, colouring, and preservatives.

Instead:

Go for real cheese especially hard cheeses such as cheddar, Swiss, or Parmesan.   Keep your serving small.

Rice cakes:

Two rice cakes offers about the same as one slice of 100% whole grain bread but without the fibre, vitamins, and minerals that you get from the bread. Rice cakes also have a high glycemic index which means they will spike blood sugar and insulin which can lead to premature hunger.

Instead:

Eat 20 almonds or raw veggies dipped in a few tablespoons of hummus.  If you love rice cakes, eat them with a

tablespoon of nut butter or thinly sliced real cheese.

https://www.theglobeandmail.com/life/health-and-fitness/health/leslie-beck-six-diet-foods-your-diet-doesnt-need/article30205984/