Diet Shakes: Sipping to Slimness

Diet shakes are called meal replacements by dietitians because, in theory, drinking one shake is intended to replace one whole meal. Other types of meal replacements are nutritional bars and pre-packaged entrees. But do meal replacements work?

Are they for you?

As a dietitian, I believe that a healthy, reduced calorie diet, along with regular exercise is the best long-term method for anyone wanting to lose weight. However, meal replacements can play a role at the start of a new eating plan or as a replacement for one meal a day. Let’s weigh up their pros and cons – as I list each, make a mental note if you can live with them or not:

Meal replacement pros
  • Single-serve pre-packaged portions make it easy to keep on track
  • You know exactly how many calories you’ve consumed
  • There’s no choice so you have no opportunity to stray
  • They are quick and convenient making them easy to use at work
  • They keep you out of the kitchen (or fast food court) and away from temptation.
Meal replacement cons
  • They don’t teach you how to make healthy choices from real food which confronts you every day
  • They don’t help you to learn the calorie content of a normal diet
  • Many are sweet tasting, encouraging a ‘sweet tooth’
  • They can get boring after a while – there are only so many “chocolate or vanilla shakes” you can take
  • They can be expensive.
Losing Weight

On paper, weight loss is easy. You really only need to eat 500 fewer calories every day to lose a pound a week. The trick is that weight loss in the real world, with busy schedules and abundant food choices, is hard. Meal replacements work on the premise that few of us know how many calories we eat each day. Packaged foods may list calorie content but most meals we eat don’t. Many of our meals may reach 700-800 calories without our realizing it. Three meals a day at 750 calories each equals 2,250 calories. An average woman needs only about 1200-1500 calories per day. The average man requires about 1500-1800 calories per day. If you add in snacks and the occasional sweets, not to mention alcohol or other high-calorie beverages like soda, most of us consume far more calories than we need.

Replacing one or two meals per day with a known quantity of calories will necessarily reduce the number of calories you consume. In other words, if instead of eating a meal that might have 750 calories, you drink a shake with 250 calories, then you will have reduced the number of calories you take in by 500. Do that every day for a week and you will lose one pound – as long as nothing else changes.

No Magic Bullet

Meal replacements are no magic bullet. As with most diets, the reason people who stop using meal replacements regain their weight is because they return to a higher caloric intake. Plus, using meal replacements doesn’t teach people how to make healthy choices about the rest of the food they eat. So, when they stop using the meal replacements, they often return to an unhealthy diet. In general, maintaining a normal weight requires learning lifelong healthy eating habits or staying on the meal replacement indefinitely. Few people want to do that.

Buyer Beware

Because meal replacements are dietary supplements, they are not regulated by the United States Food and Drug Administration (FDA). Therefore, advertisements for meal replacements may make claims about their effectiveness that are not supported by any scientific research. Also, there are no standards for the ingredients of meal replacements. Some diet shakes may be nutritionally sound, with necessary vitamins and minerals included. Others may contain only a few healthful nutrients and are about as good for you as replacing your meal with a can of cola.

My verdict

There’s certainly been an about turn in the way health professionals now view meal replacement products. Nevertheless, it’s important not to get too carried away with the results of studies to date. It’s great news that research suggests meal replacements can help people lose weight and keep it off but it’s important to remember that most study participants received additional dietary advice. Plus the very fact that someone is taking part in a study can affect their levels of motivation, with the result they are more likely to be successful.

What is clear however, is that more research still needs to be done to identify the suitability and effectiveness of meal replacement diets for ‘real-life’ situations and for people who have relatively small amounts of weight to lose.

Trying meal replacements is unlikely to do you any harm. However, for them to be successful in the long term, it’s essential you learn about what constitutes a healthy, balanced diet. Meal replacements might help you lose weight, but if you go back to eating greasy foods for breakfast, mayo-laden sandwiches for lunch and snack constantly on chips, chocolate and fast food, once you stop taking the products, the pounds will quickly pile back on.

It’s also worth bearing in mind that your taste buds might quickly get tired of the same old flavors with the result that you end up craving your favorite foods. And unfortunately, cravings brought on by denial can quickly result in binging that in turn, causes many people to ditch their dieting intentions for good.

Finally, there’s a lot to be said for getting our nutrients from food. While meal replacement products might be nutritionally balanced, there’s good evidence to suggest our bodies are better able to utilize the vitamins and minerals found naturally in foods.

Ultimately, you can’t get away from the fact that following a calorie-controlled diet based on a wide range of fresh foods including fruit, vegetables, whole grains, low-fat dairy products and lean protein-rich foods such as lean meat, skinless chicken, fish and eggs, is the cheapest, tastiest and most enjoyable way to get all the nutrients we need for good health – and to help us lose weight.

But if you still fancy trying meal replacement products, there doesn’t seem to be any reason why you shouldn’t give them a go. Nevertheless, for the best results, I suggest you use them as a kick-start to help you shift a few pounds and then switch to a longer-term healthier eating plan that allows you to enjoy eating ‘proper’ food!


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