By: Coral D. Matus, MD, FAAFP, and Svitlana Zhukivska, MD
Reprinted from the summer 2018 issue of The Ohio Family Physician.
As family physicians, we are on the “front lines” of the war against obesity. According to recent estimates, U.S. obesity rates are in the 15-20% range for children and adolescents; approximately 34% of adults are obese. Counseling about weight loss and maintenance has become a significant role for family physicians, and a working knowledge of “fad diets” is important to know in order to inform patients and help guide their weight management plans.
Low carbohydrate diets have been a fad for decades, with the popularity of the Atkin’s diet growing in the 1970s in the United States. Many variations of the low-carbohydrate, high-protein diet have surfaced over the past four decades, more specifically the “paleo” diet and the “ketogenic” diet.
One of the most popular fad diets is the paleo diet, also called the “caveman diet,” or the “stone age diet,” since it is guided by one simple question: “What would a caveman eat?” This means only consuming food that would have been available in the Paleolithic era, more than 2.6 million years ago.
The nutritional plan of the paleo diet includes anything humans could hunt for or gather, such as grass-fed meats, seafood, fresh fruits and non-starchy vegetables, eggs, nuts, and seeds. The use of healthy oils (olive, coconut, flaxseed, etc.) are also permitted. The forbidden items are those that were not easily available to Paleolithic humans, including cereal grains, (i.e. rice, wheat, rye); all dairy products; legumes (i.e. peanuts, beans); starchy vegetables (i.e. potatoes); sweets; soft drinks and fruit juices; processed and cured meats; and highly processed foods.
Some of the many “claimed” benefits of the paleo diet include the elimination of foods with preservatives, chemicals, or additives, as well as improved satisfaction of feeling full due to the high intake of fats and proteins, which are important nutrients for muscle development and a healthy immune system. The diet may also lead to weight loss, with the increased intake of protein, fruits, vegetables, and healthy fats, along with the elimination of processed foods, which are high in empty calories and carbohydrates.
The shortcomings of the paleo diet are the expenses, because food that is organically grown and grass-fed usually costs more; and an individual’s calcium intake may be inadequate, since all dairy products are eliminated. Athletes or those who have a rigorous exercise regimen may find that adequate carbohydrate intake is difficult for energy.
Since there is no portion restriction of allowed foods, overeating may occur, and adherence to the diet may be difficult due to limited food options.
The ketogenic, or “keto,” diet is a high-fat, adequate-protein, low-carbohydrate diet that in medicine is used primarily to treat difficult-to-control (refractory) epilepsy in children. The diet forces the body to burn fats rather than carbohydrates. The keto diet has been utilized for more than nine decades (since the 1920s) and is based upon an understanding of physiology and nutrition science.
While many individuals are attracted, and even enamored, by the prospect of eating steak “every day for every meal,” this also means cutting out all starchy vegetables and carbohydrates from one’s diet, and increasing consumption of healthy fats. Many sources recommend that individuals include no more than 5-10% of their calorie intake as carbohydrates, and that up to 70-80% of the calories be obtained from healthy fats (i.e. olive oil, butter, chicken fat, avocado oil, etc.), with a remaining 20-25% of calories being protein sources.
The keto diet initially made its mark treating those with refractory epilepsy. More recently, its success in attaining weight loss has become mainstream in national headlines. This diet is based on the metabolic principles that without glucose coursing through the system, the body is forced to burn fat and produce ketones instead. Once the blood levels of the ketones rise to a certain point, one officially enters into ketosis. This state results in a consistent, fairly quick weight loss until the body reaches a healthy and stable weight. There is also some evidence to support ketosis itself may have an appetite-suppressant component to it.
Another claimed benefit is the signs and symptoms of insulin resistance. One study showed that when dietary carbohydrates are restricted significantly, conversion to fat may be decreased or nearly eliminated. The result may be the improved glucose control or the increased insulin resistance in individuals with metabolic syndrome (a cluster of conditions – increased blood pressure, excess body fat, abnormal cholesterol levels, etc.), although close monitoring should be observed, since a mild ketoacidosis can lead to a more severe metabolic disturbance.
Recently, interest surrounding the keto diet in athletic performance has resurfaced. There is some thought that ketone bodies, in some instances, may provide an additional, if not alternative, fuel source during prolonged exercise when blood glucose levels are low. Ketone ester supplements will soon be available commercially, and are being marketed as a “super fuel” in the form of a drink to boost performance, promising conservation of limited carbohydrate stores for more high-intensity activity, and allowing increased endurance based on the use of ketone bodies for ongoing energy.
As family physicians who have seen the severity of illness that can accompany diabetic ketoacidosis (when the body produces excess blood acids ‘ketones’), we should inform and caution any diabetic patient who plans to follow the keto diet, or products created from it, of the risks. If this dieting does occur, we must closely monitor these patients to avoid potentially severe consequences. Although diabetic ketoacidosis does occur most frequently in Type I diabetics, it certainly can occur in ketosis prone Type 2 diabetics, as well as in those who consume excess alcohol. The resulting acidosis and severe dehydration can lead to fatal complications, such as severe dehydration, coma, and neurologic damage.
When it comes to the potential obstacles of the ketogenic diet, it can be difficult to initiate and maintain long-term. Some describe significant fatigue and discomfort during the initial phase of the diet, while many others describe improvement in energy, even from the normal baseline, once ketosis has been achieved. Strict adherence to the dietary restriction is of the utmost importance, since intermittent adherence can result in increased caloric intake (including fat), resulting in weight gain.
To compare the two, the paleo diet emphasizes the consumption of fruits, vegetables, whole foods, nuts, seeds, and healthy fats, and limits the intake of processed food, which is so prevalent in our typical “American” diet. The ketogenic diet significantly limits carbohydrates, but does not eliminate fats, which can lead to improved satisfaction of being full, and perhaps a decrease in overall daily caloric intake. Ultimately, weight loss results from decreased caloric intake combined with increased caloric expenditure. Low carbohydrate diets may assist individuals by eliminating categories of food, as well as increasing fullness due to the increased intake of protein.
As with any fitness goal in life, a diet can be maintained long-term and incorporated as a lifestyle, if desired. But, many individuals find themselves in the cycle of losing (while on a restrictive diet) and then regaining weight (when the “diet” is “over”). As family physicians, it is our responsibility to encourage patients to make healthy lifestyle changes that include adequate protein intake, low levels of saturated fats, healthy carbohydrates, and minimal to no simple sugars. In the long-term, healthy eating habits can be adopted over time. Participating in a “diet,” along with daily aerobic exercise, is the best long-term solution for weight loss and maintenance, as well as addressing the severe obesity epidemic that we have in the United States.
References available on the Ohio Academy of Family Physicians website.