Weight loss shakes have become a popular and convenient alternative to those who wish to lose the excess pounds. Because they come in ready-to-mix packs and are very simple to prepare, they are a common meal replacement alternatives to those on a diet to lose weight. Depending on the stipulated regimen, a shake can be used to replace one or two full meals a day. It has all the nutrients one needs for a balanced diet but is low in calories.

A typical weight loss shake in the market today contains no more than 200 calories, with some having as low as 90 calories. Since you need to lose more calories than you consume either through exercise or a fat loss diet in order to shed off those excess pounds, replacing two full meals with shakes that only contain 100 calories can significantly lower your caloric intake and bring you closer to your ideal weight.

Guzzling in these meal replacement shakes to lose the flab, however, is not as simple as it sounds. Here are a few things to keep in mind when you're drinking weight loss shakes or are planning to use them as part of your diet plan.

1. Watch the sugar content of the shake you use. The recommended dietary intake of sugars is 33 grams a day. Meal replacement shakes are usually marketed as low-calorie but if the variety you drink contains 8 grams of sugar, that represents a significant amount of your daily intake. If you're not careful, you could still take in more sugar than what is recommended and still gain weight even if you replace meals with these shakes. Find a shake with lower sugar content.

2. Watch the protein content of the shake you drink. If you are already eating eggs, meat and other high-protein foods, then a shake that contains 20 grams of protein could represent a significant portion of your total intake. When you eat more protein than you need, you could still gain weight. Overconsumption of protein has also been linked to kidney and liver problems although more conclusive studies still have to be performed.

3. Meal replacement shakes don't work to make you lose weight when these are not combined with an exercise regimen.

4. There are only a limited number of flavors of shakes to choose from, making the diet boring after a while.

5. Weight loss shakes don't really teach dietary changes that an individual needs to keep the weight off for the long-term. If you want to stay healthy and fit for life, you have to learn the art and science of healthy food preparation, regular exercise and a healthy lifestyle.

6. These shakes are very affordable compared to other meal plans. They are also very convenient and easy to prepare. However, they best achieve their effect when used to jumpstart weight loss.

7. The long-term side effects of these shakes have not yet been ascertained. Pending further studies, moderation is still the rule where these shakes are concerned.