Here’s a great question: If you lose weight, does it matter how you lost the weight? Preliminarily, based on the mouse work my research group is doing, the answer is, “Not really.” When you restrict the amount of calories in a low-carbohydrate diet and in a Western diet, the two actually look pretty similar, suggesting perhaps that how you cut calories is less important than that you cut calories.
When patients ask for your advice about a particular type of eating plan, remind them that diet is the sum of the whole. Fat, protein, and carbohydrates are three macronutrients that exist together.
When people eat more of one, they eat less of another, but there’s also the very important factor of just how much they eat—that is, total calories. Ultimately, we don’t say, “I’m going to eat fat at this meal; I’m going to eat protein at that meal; I’m going to eat carbohydrates at this meal.” We eat a diet; a whole meal. Be leery of painting any single dietary component as the culprit or even as the good guy. For example, tomatoes contain lycopene, which some studies suggest may protect against prostate cancer. However, lycopene—along with many of the other nutrients in tomatoes—is fat-soluble. That means if your patient eats a tomato as he would an apple, he won’t absorb many of the nutrients. He is better off eating tomatoes in the form of a sauce served with “fattening” meatballs or even on a slice of pizza with greasy cheese, because those fats will help him better absorb the tomato’s nutrients.
As we try to guide our patients toward better eating habits, we may get caught up in the mantra, “You’ve got to cut down on the fat in your diet.” But the number-one piece of advice we should be sharing is: You have to cut calories. In the 1970s and 1980s, our nation became very fat-phobic, and since then our overall fat consumption has decreased, yet obesity rates have skyrocketed. That’s because “healthy” foods often replace fat with sugar, without really saving us many calories. Also, simple sugars are more rapidly turned into fat in the body than actual dietary fat is. Obesity is the end result of caloric excess, and obesity promotes a host of medical problems, including cancer. Cutting calories reduces drivers of cancer development and progression such as inflammation, reactive oxygen species, and insulin levels.
To say that fat unequivocally equals “bad” is far too simplistic and is, fundamentally, the wrong message. The idea of cutting calories overall should be the main focus of our nutrition discussions with patients. Next would be steering them away from refined carbohydrates. I get much more worried about a patient eating a doughnut than eating a steak. Explain to the person that replacing fats with sugars is not a health-promoting strategy, and that caloric intake overall should be reduced. Remember that people can lower their serum cholesterol levels by reducing not just cholesterol intake but also sugar intake.
I’m very proud to have had a hand in influencing the nutrition guidelines from the Prostate Cancer Foundation. Those guidelines were written by four nutrition and exercise experts, and they really don’t discuss dietary fat at all. Instead, the focus is on appropriate exercise, minimizing refined carbohydrates, eating fruits and vegetables, and—most important—limiting calorie intake. When counseling your patients on weight and nutrition, this broader context is probably more useful than concentrating on the elimination or promotion of any single nutrient. n