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Protein Needs and the Problem With All Liquid Diets

There are all kinds of diets, from the all cabbage diet to the all soup diet. In the 80’s, there was a high protein, all liquid diet that was very popular, however, there were several problems noted with this plan. A better liquid protein supplement has been found, however, there still remain a number of problems with an all liquid diet of any kind, no matter how nutritious or delicious that the liquid might be. With over 34 million people listed as being obese, it is no wonder that so many different diet plans have been devised. (Source:

At any one point in the year, there are an estimated 20 million people on a diet of some kind, whether it is one that has been studied and recommended by a doctor or something of their own devices. The diet industry makes over a billion dollars every year, whether the dieters get any kind of success or not. (Source: There are problems associated with even the best of diets. Diets do not fail because of a lack of willpower – they fail because they do not look at the bigger picture. Liquid diets, high protein diets and other diet plans have problems that include:

– Addressing the actual needs of protein, fat and carbohydrates in the body

– Lack of support

– Medical risks of low calorie diets

– Medical risks of extremely high protein diets

– Why the body will always work to get what it needs

How Much of the Macronutrients Do You Really Need?

The body needs the three macronutrients, protein, carbohydrates and fat, to function properly. The body uses fat and carbs to burn for energy while protein is used in a number of other processes in the body. Protein is vital for every cell in the body and, unlike the other two, is not stored at all. New sources of protein, especially low fat, complete protein sources, must be eaten every day. Carbs, especially complex carbohydrates, should make up the bulk of the diet with about 50% of the calories. In a weight-maintenance diet (one that is meant to keep the body at its current weight), the ratio of proteins and fats should be 30% to 20%. However, in a diet that is meant to reduce weight, the amount of protein may go up to as high as 35% (the upper limit threshold) and the fat percent will go down to 15% of total calories per day. The American Heart Association’s guidelines for weight management and heart health states that the total protein in the diet should never go higher than 35% because of a number of health risks.

Everybody needs a different level of protein, however. It is a common fallacy that the bodybuilder becomes enormous from eating extreme amounts of protein. Pound for pound, a baby, aged zero to six months, needs and should get twice the amount of protein than the typical body builder. (Baby needs 2.2 grams of protein per kilogram of body weight, while the body builder needs only 1.2 grams) (Source: the US Guidelines on Protein and Diet) To determine your own protein needs, you can follow a simple formula or discuss your needs with a doctor or a nutritionist. If you are being treated for any type of medical condition or illness, you should be discussing your dietary needs with a medical care professional anyway. The formula for protein needs is:

Divide your weight in pounds by 2.2 to get your weight in kilograms. Multiply that number by.8 to get your daily protein needs in grams.

This formula is not perfect, however, and there are some factors that you should keep in mind. For instance, if you are a sedentary person, your daily protein needs will be about half (.4 grams per kg of body weight). If you are a frequent exerciser, your needs will be between.5 and.8 grams. If you are an intense exerciser or an athlete, your needs may go as high as 1 gram. Keep in mind however, that the body builder only needs between 1.2 and 1.5 grams of protein per kg of body weight. Actual protein needs will vary depending on age, gender and health status as well. The upper limit of safe protein levels is 35% of total daily calories.

The Lack of Support in Liquid Diets

Support and proper education is important in any diet plan. It is even more important in a liquid diet plan because it can be so difficult to manage. The body is meant to eat solid foods in most cases. The body wants to eat solid foods. Even the most complex liquid does not have the mouth feel that can help to trigger the satiety hormone, leptin, which cues our body that we have had enough. Most liquid diets do not have enough of the macronutrients to be complete nor do they provide enough daily calories. The bottom line for liquid diets is simple: they are great for a short term, weight loss kick off plan, meant to jump start the weight loss and get the body ready to burn up the fat. It is not a good idea or viable for most people for a long-term, lifelong solution.

The Medical Risks of Very Low Calorie Diets

Most liquid diets reportedly have between 600-800 calories on average. For most adults, the low limit threshold for health and energy is 1100 calories. (For smaller adults, this number might be slightly lower.) However, before you kick off any kind of extreme calorie reduction, you should know what your daily calorie needs are, how much energy you use through exercise each day and what can happen if you drop down below what your own body is comfortable with.

Daily calorie needs are different for everybody because of body composition and weight. A rough formula to determine this is to start with resting metabolic rate:

Multiply your desired weight in pounds by 8 and then add 200.

To find out how much energy you use through exercise:

– Multiply the number of minutes spent doing light exercise (walking, light yoga, etc) by 4.

– Multiply the number of minutes you spend doing more intense exercise, like cardio work and strength training, by 8.

– Add these two numbers together to get your daily calorie needs number. (Source: Roizen and Oz, 2006)

This is the number of calories that you need to eat every day to keep your current weight. To lose weight, you need to lower this number by about 500 calories (to lose a pound a week, a safe and achievable goal), or you could increase your exercise minutes enough to equal an additional burn of 500 calories.

Once you go lower than what your body is comfortable with, however, it will start to panic. Instead of burning the fat stores for energy like it normally would, the body may start to slow down the metabolism altogether. If there is insufficient intake of calories from all three macronutrients, the body may start taking drastic measures, thinking that it is starving and breaking down its own muscle tissue to use for energy.

Medical Risks of Extremely High Protein Diets

Just as a diet that is high in fat will lead to weight gain, diets that are extremely high in protein (defined as over 35% of total daily calories) can cause major health problems as well. It is a myth that protein only turns to muscle in the body – excessive protein can and is stored by the body as fat. In addition, high protein diets can lead to electrolyte imbalances, which in turn can lead to heart rhythm problems. Those who have diabetes and kidney disease may see more health risks from high protein diets because they can lead to the formation of the most common type of kidney stone, the calcium oxalate stone. Too much protein can cause the body to eliminate too much calcium in the urine, increasing the risk of osteoporosis in those that are prone to the disease.

Why the Body Will Always Work to Get What it Needs

The body knows what it needs. It knows how much it should eat and what kind of protein is needed for each of its processes. Regardless of how hard you try to fight against your own nature, you will always find yourself eating more than you meant to so that your body can get the protein that is required. Your body will simply continue to eat until the right amount and type of protein is met. (Source: Science Alert: Massey University)


Michael Roizen M.D. and Mehmet C. Oz. M.D. You on a Diet: the Owner’s Manual for Waist Management Free Press, a Division of Simon and Schuster, New York, New York. 2006

US Guidelines on Protein and Diet, the United States Department of Agriculture

Source by Jim Duffy

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