By Chloe Lo
With a weight loss and diet industry worth $72 billion in the United States and 45 million people going on a diet every year, it may be surprising to some that the rates of obesity are steadily climbing.[1,2] The Centers for Disease Control and Prevention reported an increased prevalence of obesity over the past 20 years, rising from 30.5% to 42.4%. So, why are we seeing this positive association between eating behaviors and weight gain (CDC)? Exploring the different dieting trends may give insight into their success, or lack thereof, and whether or not you should be trying them.
Growing in popularity, the ketogenic diet promotes consuming a high amount of fat, with up to 90% of calories coming from this macronutrient group. Some sources of unsaturated fats are allowed, like nuts and seeds, but saturated fats from oils, butter, and lard are encouraged. On the other hand, carbohydrates are strictly controlled, with an allowance of 20-50 grams per day. For some perspective, the brain needs 120-150 grams of carbohydrates per day to function normally. However, the purpose of the keto diet is for the body to reach a state of ketosis, in which ketone bodies, or fat, become the main source of energy instead of glucose. Historically, it has been utilized as a last resort treatment to cure epileptic seizures in children when medications have failed; nowadays, people are using it as a method of weight loss. But with this extreme diet comes serious risks:
Heart disease from high fat consumption
Nutritional deficiencies from a lack of fruits and vegetables
Constipation due to a lack of fiber
Liver and kidney problems from metabolizing high fat and protein
Ketoacidosis which has many complications, including a dangerously low blood pH
Altered mental status like confusion and irritation
With little evidence on the long-term health effects of the ketogenic diet, it may be more dangerous than beneficial to experiment with this trend.
Similar to the ketogenic diet, the Atkins diet consists of a high protein and fat intake, while restricting carbohydrates. This diet was developed by a cardiologist, Dr. Robert C. Atkins, in the 1960s. He believed that the typical low-fat, high-carbohydrate American diet was the cause of obesity and related health conditions. The diet continues to evolve over the years, but it is based on the concept of net carbohydrates (total carb content minus fiber content) and is supposed to be implemented in 4 phases: introduction, balancing, pre-maintenance, and lifetime maintenance. During the first 2 phases, net carbohydrates are restricted to 12-15 grams; afterwards, carbs can be increased in 10g increments every week until weight gain occurs. Thus, a person is to eat only the amount of carbohydrates that maintains their new weight. There is currently not enough evidence to support the health claims or its long-term effects, with its risks similar to the previously discussed ketogenic diet.
The Paleolithic diet was introduced in the 1970s but gained traction in the early 2000s when Loren Cordain published his book on weight loss. It is built upon the concept that humans should be consuming what was thought to be the typical diet during the paleolithic era, about 2.5 million to 10,000 years ago, before agriculture was pioneered. Foods that are acceptable to eat include lean meats, fish, fruits and vegetables, nuts, seeds, and oils from fruits and nuts. But other foods like grains, legumes, dairy products, sugar, salt, potatoes, and highly processed foods are off limits. The Paleo diet reportedly has the potential to benefit weight loss, glucose tolerance, blood pressure, and triglyceride levels, but the research remains limited on prolonged adherence. Other concerns of this diet are its restrictions of multiple food groups and a lack of consideration for geographical variations. Although the foods that the Paleo diet encourages are healthful, are the restrictions realistic for the modern human being?
Many people around the world adopt veganism or vegetarianism as what they consider to be a way of life. There are many variations, such as lacto (dairy), ovo (eggs), lacto-ovo, pescatarian (fish), and even “flexitarian” (eat meat occasionally). Individuals determine what lifestyle is the best for them; there are many motives why one chooses to be vegan or vegetarian, including ethical, environmental, or religious reasons. Health professionals are increasingly encouraging a plant-based diet for its association with lowering BMI, blood pressure, and risk for heart disease, type 2 diabetes, and cancer. It is also praised as a sustainable, environmentally-friendly diet that individuals can adopt in order to do their part in protecting the ecosystem. However, there are dietary implications that vegans or vegetarians must be aware of, one being the risk for nutrient deficiencies. Protein, calcium, iron, and vitamin B12 are the most common deficiencies seen in individuals who restrict animal products, so it may be necessary to purchase fortified foods or take nutritional supplements. Additionally, many pre-packaged vegan or vegetarian products at the grocery store may not actually be as healthy as it seems; to increase palatability, food manufacturers may add a copious amount of salt, fat, or other additives. It is important to read the nutrition label to know what exactly is in those meatless substitutes.
Another recently trending diet is intermittent fasting (IF), which is currently being studied by many researchers for its effect on health outcomes. Like many diets, there are different variations of IF; however, the basic concept focuses more so on when you eat rather than what, prolonging the amount of time between meals to encourage the burning of fat for energy. One variation is the daily approach, which limits the window of eating to 6-8 hours each day. Another variation, the 5:2 approach, consists of eating how you normally would for 5 days of the week; for the other 2 days, you’re only allowed to eat a 500-600 calorie meal each day. There are longer restrictions that require fasting for 24-72 hours, but those are much more dangerous and less common. Some of the purported health benefits from following an intermittent fasting pattern are sharper thinking and memory, heart health, and weight loss. More research on human subjects is required before these health claims can be substantiated, but there are subpopulations that are not recommended to partake in IF:
Pregnant or breastfeeding women
Children and those under the age of 18
Those with diabetes or issues with regulating blood glucose
People with a history of eating disorders
The Mediterranean diet consistently remains the eating pattern that is most widely recommended by doctors, researchers, and professional health associations, such as the American Heart Association, Dietary Guidelines for Americans, and the World Health Organization. It was recognized that people who lived in countries that bordered the Mediterranean sea had a lower prevalence of deaths from heart disease, attributing it to their dietary habits. There is no single, accepted definition of what a Mediterranean diet is, but it typically consists of:
Daily consumption of fruits and vegetables, whole grains, and healthy fats
Weekly consumption of fish, poultry, beans, and eggs
Moderate intake of dairy
Limited intake of red meats
Following this dietary pattern has been shown to have many positive health outcomes like preventing chronic diseases with no evident risks. It’s praised for its effectiveness and feasibility, with people who switch to this diet reporting high levels of satisfaction.
The Bottom Line
With so many kinds of diets, it can be confusing to know which is safe, effective, and the right one for you. A good rule of thumb is to ask yourself, “Is it sustainable? Can I adopt this diet for the rest of my life?” If not, it is most likely too restrictive and will only lead to “yo-yo dieting” that may initially result in weight loss, but ultimately lead to regaining the weight and then some. It is best to consult with your primary care provider and a registered dietitian before starting a new diet to see if it is safe and right for you.
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