Diet Reviews
By Craig Coghlin B.A., CPT, CSCS, ART®, D.C. (cand.)
Low Carbohydrate Diets
These diets became popularized with the Atkins Diet, which restricts the
carbohydrates you eat in your diet. Low carb diets have been criticized as being
no better than simple calorie reduced diets. The backbone of these diets centers
around Glycemic index.
Approximately 200 g of glucose is required by the human body every day for
its basic functions. If glucose levels dip below 40 mg/Dl in the blood, coma,
seizure, and death may occur. On the flip side, levels above 180 mg/Dl can cause
problems such as diabetes, hypertension, and atherosclerosis.
The Atkins diet is a low glycemic index diet. Atkins looks at NET carbohydrates
in a meal, which is basically the amount of carbs minus the amount of fiber in
the food. The first step in the Atkins diet is induction, which teeters into
ketosis by limiting the net carbs per day to 20 grams. This lasts for 14 days.
The next stage, ongoing weight loss, slowly reintroduces carbs into the diet by
a maximum of 5 grams per day. The patient will increase the number of carbs
until they discover the max amount of carbs they can handle while still losing
weight. The last two stages in the diet occur when the patient is close to their
ideal weight.
The South Beach Diet is another example. The first stage of this diet is to
eliminate all starches, including alcohol and fruits. The authors of the diet
say that 7-13 lbs. of weight loss can be expected in this two week stage. In the
second phase, “good” carbs are reintroduced in the form of complex carbs and
fruit. They also encourage wine with meals in this stage. The final stage is
simply maintenance. The authors assume the dieter will be able to make better
decisions now in their meal choices.
The Zone Diet is also a low glycemic index diet. Firstly the patient figures out
how much protein their body needs, then spreads this out over three meals. In
this diet the author suggests splitting the number of carbs, protein, and fat
into “blocks” and eating the same amount of blocks of each nutrient in each
meal. One major fall back of this diet is that it involves a lot of math
calculations to determine the proper amount of each nutrient to be eating at
each meal.
Other Fad / Popular Diets
The Ornish Diet involves patients being dedicated to a low-fat vegetarian diet.
Weight watchers is a generally low calorie diet that focuses on small stepwise
progressions.
So what’s wrong with these diets?
The main issue with these diets is that their long term safety and effectiveness
has not been proven. People entered into low carb diets have been shown by
several studies to lose weight, often more than people on a low fat diet, but
their may be complications with a low carb diet. One study noted that several
participants had to drop out due to a dramatic rise is LDL. The low carb
participants also reported many more adverse effects compared to the low fat
group including constipation, headaches, bad breath (due to ketosis), muscle
cramps, diarrhea, weakness, and rashes. Also, in high protein diets, the
by-product of protein metabolism is nitrogen. Too much nitrogen excretion can
damage the kidneys. Excessive protein intake also can boost uric acid
production, which can cause gout and kidney stones.
A case study was also completed that outlined a woman who had severe daily
vomiting and shortness of breath, indicating that by following the Atkins diet
she had entered into sever ketoacidosis. Dietary ketosis is a normal phenomenon,
but diabetic ketoacidosis can be life threatening. Thus, for a
iabetic person that enters into this diet (whether they are aware of their
condition or not) and subsequently increase the ketone bodies in their system,
there could be an overload. When excessive ketones are produced, the kidneys
have to work harder to filter them. The body goes into starvation mode and
metabolism slows down. Then carbohydrates are burned more slowly. Many
supporters of the Atkins diet though claim that the ketones produced would be at
a level too low to cause acidosis.
The reported weight loss in low carb diets has been argued as well. Many critics
conclude that the weight loss people experience in these diets is not from the
restriction in carbs but rather the decrease in calories and length of diet.
They also note that the low carb diets cause increased weight loss in 3-6
months, but thereafter, the weight loss is no different than a normal calorie
reduced diet. Some might also argue that the increased initial weight loss is in
large part the water retained with the carbs (with every one gram of carbs, the
body stores 3 grams of carbs). Yet as usual, the research seems split as to the
direct safety of the Atkins diet. Some claim that HDL levels, triglyceride
concentrations, and insulin sensitivity are all improved, while other report the
opposite.
The main downfall of the Atkins diet that no one can deny is in its nutritional
deficiencies
—too much fat and saturated fat, too little fiber, too few fruits. The South
Beach and Jenny Craig diet plans are lacking in any sort of clinical evidence.
As mentioned earlier, the biggest problem with all of these diets is simply the
adherence. In many of the randomized studies, drop-out rates were as high as
45%. And those that did manage to stay with the diet were not very strict in
following the diet exactly as it requests.