Many of us would love to shed a few pounds and feel better. Is dieting the answer? We asked Lisa Muras, a registered dietitian with Virginia Hospital Center’s Outpatient Diabetes & Nutrition Program, to weigh in.
The Mediterranean Diet
What is it?
This style of eating follows the diets of people who live in the countries along the Mediterranean Sea. There are no specific food restrictions. Rather, it’s a framework emphasizing minimally processed, mostly plant-based foods such as fruits, vegetables, nuts and whole grains; fish and dairy (such as yogurt and cheese); and a high amount of healthy fats—principally olive oil. Whole grains such as wheat, oats and barley are served at most meals; nuts, beans, legumes and seeds are eaten daily; and herbs and spices are used liberally and in place of added salt. Fish and shellfish are important protein sources, while meat is eaten in smaller portions. Sweets are consumed in small amounts and fruit can be a substitute for sweetened desserts. Wine is consumed in moderation, but water is the primary beverage. This diet emphasizes cooking at home and using local ingredients. It also promotes the social and mindful aspects of enjoying food, like sitting down to meals and enjoying meals in the company of others.
Pros:
Mediterranean diets have stood the test of time. Long-term research has shown remarkable health outcomes associated with this style of eating, including increased life span, improved brain function, better eye health, lower risk of certain cancers, decreased risk of heart disease and diabetes, lower levels of blood pressure and LDL cholesterol, protection against Alzheimer’s and Parkinson’s diseases, improved rheumatoid arthritis and greater fertility. The traditional Mediterranean diet is high in monounsaturated fatty acids, antioxidants, phytochemicals such as carotenoids and anthocyanins, vitamin C, tocopherols (vitamin E), polyphenols (flavonoids) and dietary fiber. Despite the presence of heart-healthy fats, many people lose weight on the Mediterranean diet because they do not feel deprived or hungry.
Cons:
It’s important to remember that Mediterranean eating is a dietary pattern, meaning that adding one or two Mediterranean food components while still maintaining a mostly Western diet (pepperoni pizza with a glass of red wine, for example) will not provide much benefit. It can sometimes be difficult to recognize whether a food fits into the Mediterranean pattern, as there are no set “rules” to follow, leaving some feeling lost. The shift to Mediterranean can be a dramatic change for people who don’t like (or know how) to cook and plan meals; there may be a steep learning curve. Also, some of the recommended foods can be expensive, such as olive oil, seafood and avocados.
Bottom line:
The Mediterranean eating pattern isn’t really a fad diet; it’s been around for centuries and has consistently been shown to promote good health. It doesn’t restrict food groups, allows for occasional treats in moderation and encourages a healthy outlook toward food.
The Paleo Diet
What is it?
A diet based on foods that were supposedly consumed by humans in the Paleolithic age, Paleo puts a heavy emphasis on meat, fish and plants while cutting out dairy, grains, legumes and processed foods.
Pros:
This diet includes reducing processed foods and refined sugar, which are associated with obesity, heart disease, elevated blood glucose and other chronic conditions. The 2015-2020 Dietary Guidelines for Americans (DGA) recommend that Americans consume less than 10 percent of their daily calories from added sugar. Following an eating pattern such as Paleo would help reduce these unnecessary calories.
Cons:
Any diet that eliminates entire food groups—in this case, dairy and most carbohydrates—is suspect. Many people find it difficult to adhere to such restrictions long term, and omitting those foods can lead to nutritional deficiencies such as a lack of B vitamins (for example, folate, niacin and riboflavin), fiber, calcium and vitamin D. This diet demonizes all grains, even though current research indicates whole grains are associated with a reduced risk of coronary heart disease, cancers, respiratory and infectious diseases and diabetes, and have been shown to help reduce inflammation. It also forbids legumes, including beans, lentils and peas, which are associated with a reduced risk of obesity and chronic diseases. Whole grains and legumes also promote bowel regularity, increased satiety and more variety in eating patterns.
Bottom line:
In today’s society it is not possible to eat exactly as our ancestors ate (and who knows what they really ate?). A much more sedentary lifestyle, a high-tech food supply and lack of wild game further complicate this notion. Pick and choose some elements of this diet, such as adding more fruits and vegetables, but ignore unfounded claims regarding complex carbohydrates.
The Keto Diet
What is it?
The ketogenic, or Keto diet, has been around for almost 100 years. It was originally used to reduce the severity of seizures in young patients with epilepsy. The diet promotes a high fat intake, with fat accounting for 65 to 80 percent of daily calories, while protein makes up 15 to 25 percent, and carbohydrates are restricted to just 5 to 15 percent. That’s only about 20 to 50 grams of carbs per day (compared with the average amount of 245 grams), or no more than 1/2 to 1 cup of rice per day. The idea is to put the body into ketosis—the burning of fat instead of glucose for fuel. Normally, the human body uses glucose as its primary energy source, but when carbohydrates—which turn into glucose or sugar—are severely restricted, the body then uses fat for energy and produces ketones as a byproduct. In a truly ketogenic diet, individuals would be checking their urine for the presence of ketones to make sure they are using fat as their main energy source.
Pros:
The ketogenic diet reduces insulin secretion and some research indicates it is an effective tool for lowering blood sugar in people with diabetes. One recent study involving subjects with diabetes who followed a ketogenic diet found some participants lowered their hemoglobin A1c (average blood sugar over a three-month period) to target levels and a loss of 12 percent of their body weight. Besides experiencing reduced blood glucose, individuals following the Keto diet report decreased cravings and hunger. It isn’t clear if this is the result of increased satiety from the high levels of fat, or because of the actual ketones. In the short term, it appears effective for weight loss.
Cons:
There are no long-term studies on the ketogenic diet for weight loss or blood sugar control. Some research suggests that participants may lose weight, but typically gain it back once they stop the diet. Furthermore, there is no standard Keto diet. The recommended carbohydrate intake varies, so it can be difficult to compare results. Nutrient deficiencies are also a concern, including potassium (found in vegetables such as potatoes, fruits and beans), B vitamins, fiber and prebiotics, which aid the growth of beneficial microorganisms for better gut health. Some studies have tied the Keto approach to an elevation in LDL (“bad”) cholesterol and triglycerides—so if you’re using saturated fats such as butter, cream and animal fats as your primary fat source, you could be at increased risk for cardiovascular disease. And as with other trendy diets, restricting carbohydrates can be hard to stay with over time.
Bottom line:
Some aspects of the Keto diet can be beneficial. Since carbohydrates typically make up 50 percent of our calories, consuming less of them can help with weight loss, and most people will see health benefits when avoiding refined carbs such as desserts, potato chips or pizza. However, it’s best not to eliminate slow-digesting carbs such as fruit, legumes and whole grains.
Intermittent Fasting
What is it?
Fasting is generally defined as abstinence from all or certain foods and/or beverages for a specified period of time. It has been practiced for centuries, often as part of religious practice. When used as a weight loss method, fasting can take many forms: alternate day fasting (fasting for 24 hours, then eating normally for the next 24 hours); modified fasting such as the 5:2 diet (eat normally but healthfully for five days of the week and consume a very low-calorie diet of 500 to 600 calories on two nonconsecutive days); or time-restricted fasting (eating only during a specific time frame, such as 10 a.m. to 6 p.m.).
Pros:
A large body of research exists on laboratory animals showing that some types of fasting can reduce the risk of diseases such as diabetes, cardiovascular disease, Parkinson’s disease and stroke. Some small studies on humans have shown significant short-term weight loss, decreases in body fat and a reduction in triglycerides, LDL cholesterol and systolic blood pressure. It is believed that fasting may lead to improved health because it positively influences circadian rhythms (thus improving sleep), and helps activate adaptive stress responses to protect against disease. Traditional daily caloric restriction can slow your metabolism rate, but eating normally most days of the week with fasting two or three days may actually accelerate metabolism.
Cons:
Most meaningful research has been conducted on animals, so the results of a fasting diet on human subjects is unclear. Also, the term “fasting” is widely interpreted, so it is difficult to compare results. While some research indicates intermittent fasting can be effective for short-term weight loss, it doesn’t appear to be effective in keeping the weight off over time. Adherents to this diet may find it difficult not to overeat or “cheat” on non-fasting days, which can thwart weight loss. Also, many following a fasting “window” tend to skip breakfast, which has been shown to increase the risk of cardiovascular disease while decreasing cognitive function and energy. On fasting days, many individuals report feelings of lethargy, headaches and low blood glucose, although this can improve over time. A well-rounded eating pattern provides both calories (energy) and micronutrients, such as vitamins and minerals, that would be missing when fasting and difficult for most people to meet in one day.
Bottom line:
Going longer between meals and snacks may be beneficial, particularly if you struggle with late-night snacking. The constant “grazing” that typifies a Western diet complicates metabolism, adds excess calories and can even disrupt sleep. Fasting in the evening and overnight, then eating regular meals during the day, is the pattern that appears to have the most benefits in terms of weight loss, blood sugar control and improved lipids. It’s also the most tolerable.
Whole30
What is it?
This diet promotes eating fresh foods while eliminating anything processed—including all grains, dairy, soy, legumes, sugar, certain preservatives and artificial sweeteners. According to Melissa and Dallas Hartwig, authors of The Whole30: The 30-Day Guide to Total Health and Food Freedom, the list of foods to be eliminated cause a variety of health problems including hormonal and gut imbalances, inflammation and weight gain. By following the Whole30 plan for 30 days, they claim participants can improve digestion, skin health, metabolism and fitness. The daily eating plan consists of three meals with modest portions of protein, fruits, vegetables, nuts and seeds, plus fats from oils, clarified butter, coconut and olives. At the end of the 30 days, eliminated foods can be slowly reintroduced, depending on how your body responds to them.
Pros:
As with Paleo, reducing processed and refined foods is a good step toward improving overall health and is often associated with weight loss. The emphasis on whole foods adds fiber, cancer-cell-fighting phytochemicals and antioxidants to your diet.
Cons:
Even though it is meant to be a “temporary” diet or followed only occasionally, Whole30 is quite restrictive. Disallowing any type of treat (including homemade ones!) often backfires, making the restricted food even more desirable. This diet also encourages the use of saturated fats such as clarified butter, lard and coconut oil, and saturated fats have been shown to increase LDL (“bad”) cholesterol, which can increase the risk of heart disease. Strong evidence shows that replacing saturated fats with unsaturated fats (for example, using peanut butter on your toast instead of butter) can help improve your lipid profile and reduce your risk of cardiovascular disease. However, peanuts, and indeed all legumes, are not allowed on the Whole30 diet.
Bottom line:
Whole30 takes many highly nutritious foods, such as whole grains, legumes and dairy, and kicks them to the curb. These types of elimination diets can set up a negative relationship with food, putting “good/bad” labels on many foods—even ones that can be healthy. Seeing food as the enemy, or as something that is never allowed to cross your lips, can set some people up for eating disorders or at the very least a gloomy outlook at mealtime.