Popular Diets-What do the Experts Say?
With the holidays behind us, many people are thinking about ways they can improve their health in the new year by changing their diet. There are hundreds of coaches and “experts” out there advocating one way or another to drop pounds or tone up. But do any of these diets live up to their claims?
Clean eating is different from most diets in that it does not advocate for or limit any particular nutrient (i.e carbohydrate, protein, or fat). It is a subjective term that places an emphasis on eating minimally processed foods as close to their natural form as possible. So, simply speaking, a bowl of fruit is #cleaneating, whereas a bowl of fruity pebbles is… #not.
I believe this trend has good intentions. Any dietitian will likely recommend you try to prepare more foods at home and eat fewer packaged and processed foods. But the line between whole and processed is blurry. Technically, roasted vegetables, whole-wheat bread, and boneless, skinless chicken breast are processed. Other definitions of clean eating suggest that it is only the ultra-processed foods we should avoid. These include foods with added sugars, preservatives, and ingredients you cannot pronounce. Again, this has good intentions. One drawback of this definition is that it places judgment on the foods we eat, and suggests if we don’t eat “clean” we are somehow consuming foods that are “dirty”, or those that will harm us. But this is not the case. There is room in a diet for all types of food, and many ultra-processed foods can offer the benefit of cost and convenience for many people. For example, whole-grain cereals, instant rice, canned fruits and vegetables, and some frozen lunch entrees are all processed foods that can offer a variety of nutrients at a low price. Furthermore, this type of black-and-white thinking can lead to disordered eating and full-blown eating disorders, such as orthorexia, or the obsession with healthy eating.
The ketogenic diet (AKA “keto”) is a high fat, very-low carbohydrate diet originally identified in the treatment of seizures, though it is recently gaining traction in both the athletic and weight management realms. When carbohydrates are not available, your body is forced to break down fat for energy, resulting in the production of ketones (hence, “ketogenic”). Advocates claim that this diet is the solution to obesity and chronic disease. This is somewhat true, at least in the beginning. For the first week or two following a ketogenic diet (or any low carbohydrate diet), your weight will drop rapidly. This is due to the large water content of carbohydrates-when you cut out carbohydrates, you not only lose a large portion of calories in your day, but you lose a significant amount of associated water weight. In addition, ketones may suppress appetite, leading you to eat less over the course of a day (1). There is even evidence that following this pattern may actually improve cholesterol levels, at least in the short-term (2,3,4). Sounds like the holy grail of diets! So, should you drop the green smoothies in favor of this radical approach? Not necessarily. The ketogenic diet is not a high protein diet, as the media may lead you to believe. A typical day may include 1-2 cups of non-starchy vegetables, a few eggs, no more than 6-7 ounces of beef, and a whole lot of butter, oil, and cream. This is actually less protein than a typical American consumes!
The ketogenic diet has only been studied over the short-term (about one year), and there is no evidence of how cholesterol and blood sugar levels may change as time goes on. One year is not truly long-term, when you think about a lifespan. Since the ketogenic diet nearly eliminates carbohydrates, followers will have trouble getting adequate fiber, which is critical to the health of the gut microbiome and preventing certain types of chronic disease such as cancer and cardiovascular disease.
Finally, long-term sustainability is a concern when it comes to the ketogenic diet. It is incredibly restrictive and may interfere with quality of life. And, like the clean eating trend, it can lead to obsessive and disordered eating behaviors.
The ketogenic diet is still in its early stages of research. In the mean time, experiment with some “keto-friendly” recipes if you’d like, but stick with a more moderate approach to nutrition and aim to include a variety of food groups, including fruits, vegetables, whole grains, lean proteins, and heart-healthy fats such as olive oil and nuts/seeds.
Intermittent fasting is a trend gaining popularity due to its claim to promote weight loss, improve lab values such as cholesterol and blood sugar, and prolong life. Interestingly, it does not dictate how many calories to eat nor what foods to include, but focuses instead on when you eat. There is no standard definition for intermittent fasting but all versions of this pattern restrict eating to a specific time period. This may include 2 days of caloric restriction (up to 500 calories per day) and 5 days of “normal” eating; restricting food intake to 8 hours within a 24-hour period; or restricting calories every other day.
Based on the available evidence, this method may deliver on the first two claims. A small study (32 participants) found that alternate-day fasting in particular may result in gradual weight loss (one pound per week) and improvement in triglyceride and cholesterol levels (5). Keep in mind that intermittent fasting decreases total calorie intake over the course of a week, which likely played a role in the weight loss and lead to cholesterol improvements. This study also had a small sample size, and was only done over the short-term (12 weeks). As discussed above, the question then becomes whether the dieter wants to follow this pattern for the rest of his or her life. Theoretically, as soon as you return to a “normal” eating pattern, weight will be restored.
The long term data on this pattern of eating remains mixed. Intermittent fasting may offer a more manageable way of calorie restriction for some. On the other hand, it may set some individuals up to regain weight more easily. This way of eating also poses risks for individuals taking certain medications. For example, those with diabetes taking insulin or other blood-sugar lowering medications are at increased risk for low blood sugar on fasting days (6). Always consult with your doctor before changing your eating habits or pattern in such a way.
So are all “fad” diets doomed? Not necessarily. Any diet that catches your attention and gets you thinking about ways to improve your health has good intentions! When evaluating dieting trends, try to think realistically and consider how a particular diet would fit into your lifestyle. If you are a pasta lover, then the ketogenic diet would probably not be a great fit. But if you are trying to include more fresh foods in your diet, clean eating may offer some useful resources. Consider meeting with a registered, licensed dietitian to help you sort through the confusion and choose a plan that works well for you.
Are you tired of trying diet after diet only to regain the weight and then more? This is known as the “dieting cycle”, or cycle of restriction and overeating. Our registered dietitians will work with you to break this cycle and develop a plan that fits with your lifestyle. They will provide you the support, accountability, and problem-solving strategies that you need to reach your goals. Make an appointment today and never say the word “diet” again!