Chris Horlacher presents a favorable review of a high protein/high fat diet in his recent blog post on fat consumption. In the interest of presenting a full range of viewpoints, I thought I might briefly discuss some of the counter-evidence, and make a recommendation for a balanced, common-sense nutritional plan.
As a type 1 diabetic, I differ remarkably from Horlacher. For one thing, my condition entitles me to regular consultations with professional dietitians. For another thing, being a diabetic exposes me to a daily risk of falling into ketosis, and I therefore question the wisdom of using ketones as an energy source. More on that in a moment. First, letâ€™s take a brief look at protein.
Protein Absorption and Energy
There is a limit to how much protein the body can absorb. Excess dietary protein is inefficiently converted into glucose – which can be used for energy – ketones (more on them a little later), and ammonia, which is toxic and must first be processed by the liver and kidneys before being expelled from the body as urea.
The conversion of amino acids to glucose and ketones is not an efficient process. Because most people consume carbohydrates in some form or another, the bodyâ€™s â€œfirst stopâ€ for energy is the glucose metabolized from those carbohydrates. If a personâ€™s energy needs are fully met by carbohydrate intake, whatever glucose has been converted from dietary protein is simply stored as body fat.
Fat storage is the bodyâ€™s next stop for energy, but it must first be re-converted to glucose. During lengthy, strenuous exercise or other periods of rapid fat metabolization, calories from fat cannot always be used for energy (for technical reasons). The body resorts to ketones, a byproduct of protein synthesis.
Only if oneâ€™s energy needs are not met by carbohydrate intake and fat metabolization will the body move to alternative energy sources, such as protein. At this stage in the process, however, the only dietary protein being metabolized is whatever happens to currently exist in the blood stream. If little or none is present, then the body will metabolize muscle tissue to feed itself.
This phenomenon is not widely regarded as a healthy state of being. Trained distance runners, for example, must run in excess of two hours straight before their bodies resort to metabolizing muscle tissue. Pregnant women experience ketosis if they are not eating adequate amounts of carbohydrate or protein. Starving people experience ketosis, as do untreated diabetics.
Most people experience noticeable discomfort under such conditions. It is not pleasant.
Inducing an emergency metabolic state that cannibalizes muscle tissue is, to put it mildly, a heterodox approach to health and fitness.
There is no question that inducing ketosis will result in weight loss. But is such weight loss healthy?
Consider the pictures below. On the left, you see yours truly at 135 pounds, in a state of advanced ketosis. On the right, you see me after six months of insulin therapy and getting between 50% and 60% of my total daily calories from carbohydrates. At that point, I weighed 148 pounds and was smack-dab in the middle of the recommended Body Mass Index range.
High blood sugar – even extremely high blood sugar – poses no direct threat to the body in the short-run. It is long-run elevated blood sugar, on the other hand, that results in diabetic co-morbidities. For diabetics like me, it is ketosis that results in short-run damage. Left untreated, it becomes life-threatening and coma-inducing.
I could cite any number of scholarly journals here, but they are a mere Google search away, and sometimes a picture is worth many times its weight in words. What the pictures do not depict are the pervasive fatigue, constant dizziness, difficulty breathing, unbearable thirst, unyielding polyuria, increased heart rate and increased blood pressure I experienced as a direct result of ketosis. All of these symptoms are ready to return within hours of a missed insulin injection.
The point here is that, notwithstanding the associated weight loss, is damaging to the body. Much as tapeworms, poisoning, cancer, or stress all produce weight loss at the expense of actual health, so ketosis results in weight loss at the expense of the kind of damage I experienced between the months of July and October, 2009.
In fact, monitoring my body weight is an important responsibility I have as a type 1 diabetic to ensure that I am not experiencing ketosis.
As you can see, we diabetics view the idea of a self-induced, voluntary ketosis with extreme criticism. Non-diabetic advocates of low-carbohydrate diets, insulated from the immediate threat of coma, sometimes make excuses here. Because the long-term physical toll of ketosis does not also come with a 4-times-a-day insulin injection, perhaps they lose sight of the real long-terms risks to which they are exposed.
Diet, Weight Loss, and Health
All of this begs the question: Is mere weight loss the goal of all diets and exercise regimens, or is there something else to it?
I often find myself at odds with many in the pop-fitness community, who tend to recommend low-carb diets, weight training, and high-intensity interval training (HIIT) exclusively. Such advice centers around burning a lot of calories and losing a lot of weight. It makes for a great sound-bite, but what do you do once you achieve a healthy weight? Lose more weight? Burn more calories? Eat more protein and fat?
While some of us surely could stand to lose a little weight, not all people need to do so. Inducing ketosis in such circumstances defies medical science and common sense. Choosing the path that results in the greatest weight loss in the shortest period of time by no means results in an optimal health strategy, and losing a great deal of weight in a short period of time is often the sign of real medical problems.
Itâ€™s important to keep in mind the real goal of diet and exercise: long-term health. â€œLong-term healthâ€ means being fit and free of illness for decades. That means having a healthy and sustainable diet and exercise regimen, one that you enjoy, one that poses few long-term health risks. While no one may ever agree on the “correct” percentage of calories that ought to come from fat, protein, and carbohydrate, it is important to stay aware the serious health risks associated with abnormal metabolic conditions.