Diet 101: Slim Fast

Meal replacement diets like Slim Fast were all the rage in the 1990s. You might remember friends and coworkers whipping out cans of the liquid shakes during lunch breaks. So are liquid meal replacements a thing of the past or can they be a healthy way to lose weight?
Meal replacement diets like Slim Fast were all the rage in the 1990s. You might remember friends and coworkers whipping out cans of the liquid shakes during lunch breaks. So are liquid meal replacements a thing of the past or can they be a healthy way to lose weight?

Founded in 1977, the Slim Fast plan was designed to help folks lose weight quickly (hence the name). In 2000, Unilever bought the company for a few billion and now sells more than 50 branded products worldwide.

Here is the basic idea: Consume two shakes or meals bars, a sensible, regular meal and three healthy snacks every day. The theory behind the meal replacement shakes and bars is that they contain an “HC4 formula,” which is a special combination of protein, fiber and fat. It’s supposed to control hunger for up to four hours, help you resist cravings and ultimately lose weight. The promoted rate of weight-loss is between one to two pounds per week.

Typically, breakfast is the meal you replace with a shake or bar (they run around 180 to 200 calories). Lunch can be a combo of a healthy meal and a meal replacement (like a half sandwich and a shake). Dinner should be a 500-calorie, “sensible” meal that includes veggies, a lean meat and whole grains. Snacks are essential and usually consist of fruit or veggies, which you may sometimes pair with a snack bar. Overall, you're getting about 1,200 calories per day, but this can vary depending on your height, weight and activity level.

When I checked out the Slim Fast site, here's the meal plan it suggested:

Breakfast: 1 Slim Fast Optima Shake

Snack: 1/2 banana
Lunch: 1/2 turkey sandwich and Slim Fast Optima Shake
Snack: 1 cup carrots and Slim Fast Optima snack bar
Dinner: A 500-calorie meal with a vegetable, starch and protein

Snack: 1 cup grapes
The Costs

Slim Fast has a free website that you can join if you provide some personal information. Features include a personalize meal plan, fitness planner, community access, shopping list and online support, including a section to ask registered dietitians personalized questions. You can also use specialized tools such as a weight calculator, which helps you set weight-loss goals in time for a big event (say, a wedding or graduation).

Sites like sell Slim Fast shakes and bars on and you'll usually find them at your local drug store or market. A container of three Slim-Fast Optima Meal Shake Mixes runs about $24.99. I also found eight boxes of the 100-calorie snack bars (six bars per box) for $29. Considering you're eating a few of these a day, this can quickly add up to about $200 per month. Don’t think you’re getting higher quality meals in these cans, either — some of the shakes contain more than five teaspoons of sugar along with various preservatives.

The Good

- There are to grab-and-go meals and snacks.

- Daily calories are reasonable.

- Recipes can be prepared in 15 minutes or less.

The Not-So Good

- There’s not much whole, natural food on this plan.

- You're getting a laundry-list of chemicals and preservatives in the suggested shakes and bars.

- Bars and shakes are not so tasty!

- Meals and snacks are limited and become repetitive.

- Many folks can’t stick to the calories limit or control portions after going off the plan.

- It doesn’t teach you how to eat healthfully over the long-term.

Bottom Line:

A diet that directs you to primarily eat meal replacements is not teaching you how to eat for the rest of your life. How long can you stay on shakes and bars? You’d be better off learning how to eat moderate portions of real, wholesome food.

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