Jeffrey Bland, PhD, breaks down why two contradictory diet studies in major journals miss the point. They compare macronutrient percentages but ignore what matters: whether your carbs are whole grains or refined, your fats are omega-3s or trans fats. He recommends Mediterranean-style eating with minimally processed foods instead.
So I have a gripe. I bet you have this same gripe. This relates to that four letter word diet, diet and its relationship to weight loss. So were you confused when two of the preeminent medical journals on consecutive days published what appear to be contradictory studies? I was confused. First, the Annals of Internal Medicine publishes studies showing that when they looked at various diet interventions, that a diet higher in fat and lower in calories produced the better weight loss and had a more salutary or beneficial effect on cardiovascular risk factors. Hmm. Study number one. Study number two, equally prestigious medical journal, the Journal of the American Medical association, paper entitled Comparison of Weight Loss among named Diet Programs in Overweight and Obese Adults. A meta analysis of many studies. And what did this paper come to the conclusion of? Well, it really doesn't matter whether it's higher in protein or higher in carbohydrate or higher in fat that all these diets will produce the same weight loss as long as you cut calories. So the composition doesn't matter. Now, what's my gripe? My gripe is that both of these studies are not that important and they don't really give us any clarity about what the real story is as it relates to diet and weight loss. They actually just contribute to increased confusion without clarity. Why am I saying that? Because we recognize, based on hundreds of studies that have been done over the last 10 years, that it's not just the percent protein, carbohydrate and fat in the diet that controls the effectiveness on regulating metabolism and weight and weight loss. It's the composition or the type of protein. Fat, carbohydrate plays a very important role. Now what do I mean by that? Let's use protein as an example. Let's say that all we're worried about is the percent of calories of protein in the diet. That was the only determinant. Then what happens if a person then eats grain proteins that contain gluten and they are a gluten sensitive individual? Do you think they're going to have a good metabolic outcome? Of course they won't. They'll have an adverse effect. So the type of protein plays an important role, not just the magnitude of protein. Similarly, with we know omega 3 fatty acids that come from, say fish oils and vegetable oils have a much better effect on thermogenic response, meaning burning the fat as calories of heat than do long chain saturated fatty acids from animal fats. And therefore it's not just a percentage of fat calories, it's the type of fat that relates to their metabolic efficiency. And similarly for carbohydrate, we know that if it's a carbohydrate calories come as sugar. That has a very different effect on metabolism than if the same number of calories come as partially processed, highly unrefined, complex carbohydrate, rich vitamin, mineral and fiber rich plant carbohydrate, whole grain starches. That has a very different effect on metabolism. So what's the takeaway from this? The takeaway is, oh my word. No wonder we're all confused. When we see studies coming from journals of this reputation that just lead to increasing contradiction and confusion. Without addressing the real issue, which is the composition of the diet based upon the type of protein, carbohydrate and fat, it doesn't help us out at all. In fact, the best studies are those that are done on diets that are complex, like the Mediterranean diet, which has a lot of carbohydrate, but it's minimally processed and highly unrefined with all vitamins, minerals and fiber. It has a lot of omega 3 fats and it has protein that's balanced in essential amino acids. Those type of diet studies, what do they show? The best normalization of metabolism, weight loss and control of risk factors associated with diabetes and heart disease. Those are the studies that help answer the question what type of diet we should be on. These other studies that don't even look at the composition of protein, carbohydrate and fat and just give us some kind of a number, they only lead to confusion. So don't be misled. Stay with the complexity of diet, with the fact that we know that the appropriate minimum, refined, highly unprocessed fruits and vegetable, grain based minimum, animal protein and rich in omega 3 fats diet which are high in vitamins and minerals and fiber, that's the solution to this problem.
