This blog should more appropriately be titled my rant of the month:
How many diet fads come out every year? Atkins, Zone, Paleo, Low-fat, South Beach, Intermittent Fasting are some of the most popular, but there are hundreds more pumped out every year. Why do we have new diets every year? Because there is not, nor will there ever be, a diet that can guarantee weight loss. Researchers keep making weight loss a scientific endeavor. The researchers then publish the findings, sell books, get rich and then the diet fades. Enough already, weight loss is not rocket science. It’s simple: balance energy by eating better and getting off of your ass. To prove my point let’s compare the data on a controversial issue: high-protein, low-carbohydrate vs. low-fat diets.
In 2002 a study done from Duke University researchers comparing a high protein low carb diet versus a traditional low-fat diet. The results of this study became much publicized and launched the Atkins Diet revolution. It hit mainstream media with a left and right hook. The diet quickly became one of the best-selling diet plans of all-time. But pundits refuted the data stating unreliable and invalid data. Today, there is valid points of discussion made by both sides.
Like most research and controversial issue, the data is for and against the high-protein diet is equivocal. In 2003, the New England Journal of Medicine published two studies which compared a low-carbohydrate diet to a calorie-restricted, low-fat diet in obese adults (1, 2). After six months both studies showed that low-carbohydrate subjects lost more weight and had significant reductions in markers for cardiovascular disease. This includes decreased triglyceride levels. However, after one year of performing the diets, weight loss and triglyceride levels were similar. But like many diets, compliance is an issue and in both studies there was a high dropout rate – thus data is unreliable.
As I had mentioned, pundits refuted the data. Most stated, that carbohydrate restriction was not the reason for weight loss, rather it was attributed to calorie deficit. This is similar to the systematic literature review done by Bravata, et al concluded that participant weight loss on low-carbohydrate diets was a result of caloric restriction, but carbohydrate restriction (3).
So Atkins, does yield weight loss, but why? Can I really eat a bacon cheeseburger (with no bun) and lose weight? Physiologically, carbohydrates are the body’s primary fuel source. When we eat carbohydrates the food is broken down and stored in skeletal muscle tissue and liver as glycogen, an easy to use energy source. When we eliminate carbohydrates from our diet we also eliminate glycogen stores. Without glycogen, our body must use fat as energy. Subsequently, our body enters a state of ketosis – a state where ketone bodies are produced when fatty acids are broken down for energy. The loss of glycogen stores – and associated water loss – coupled with increased fat metabolism creates weight loss. In addition, the breakdown of fat is much more difficult than breaking down glycogen. Thus, our body must expend more energy to convert fat to energy (4) – burn energy to create energy.
But there are risks to eating a high-protein, low carbohydrate diet, right? The answer is yes and no. Many have stated a high-protein diet causes kidney and liver issues as well as abnormal insulin metabolism. Levine et al performed a research review on low-carbohydrate diets and found little data to say a high-protein, low-carbohydrate diet causes health concerns (5). However, many studies have found that the diet does cause common side effects such as constipation, nausea, weakness, dehydration, and fatigue.
Is there a winning diet method? Simply put – the answer is no. While South Beach, the Zone, Atkins and others have all remained the most popular, there is not winner. If there were some magical remedy we would never again have new diet fads. After reviewing all of the data there is one constant: all weight loss is associated with negative energy balance. Meaning, you are burning more calories than you are consuming.
Remember Super-Size Me? The guy who ate McDonald’s everyday and gained weight. Well have you heard of Doug Logeais? He ate McDonald’s everyday for 30 days and lost weight! How, he exercised. He trained most days of the week at a high intensity – he burned more calories than he consumed. Has anyone seen Michael Phelps’ diet? Big Mac, Pizza, soda, ice cream, 10,000 calories per day in food, but nobody says he has a weight problem. He is a long, lean and the greatest Olympic athlete of all time. Does he need to change his diet? Can you honestly say that he is doing something wrong? He is fit because his exercise off-sets calorie consumption.
My final opinion: regular physical activity combined with a well-balanced diet is paramount. Weight maintenance requires permanent changes to eating habits and increased physical activity. The specific strategies for making those changes, and making them permanent, will vary from person to person. So, instead of a walking through the local book store of the best-selling diet book, save your money. Take a walk through your neighborhood. Instead of cheeseburger and fries – order a turkey burger and side salad. This is not rocket science – quit trying to make it more difficult than it is.
1 Samaha FF, Iqbal N, Seshadri P, et al. A low-carbohydrate as compared with a low-fat diet in severe obesity. N Engl J Med. 2003;348:2074–2081.
2 Foster GD, Wyatt HR, Hill JO, et al. A randomized trial of a low-carbohydrate diet for obesity. N Engl J Med. 2003;348:2082–2090.
3 Bravata DM, Sanders L, Huang J, et al. Efficacy and safety of low-carbohydrate diets: a systematic review. JAMA. 2003;289(14):1837–1850.
4 Buchholz AC, Schoeller DA. Is a calorie a calorie? Am J Clin Nutr. 2004;79(suppl):899S–906S.
5 Levine MJ, Jones JM, Lineback DR. Low-carbohydrate diets: assessing the science and knowledge gaps, summary of an ILSI North America workshop. J Am Diet Assoc. 2006;106:2086–2094.