Short term studies of the Atkins low carbohydrate diet were very encouraging. Not only were patients losing more weight, but their metabolic profiles were improved compared to the low fat diets of years past. Millions of people were taking a low carbohydrate lifestyle, and seeming to enjoy the benefits. By the mid 2000’s, Dr. Atkins long dreamed Diet Revolution was well and truly underway. Not only did short term studies show better weight loss, but better metabolic profiles. Yet another study, published in the prestigious New England Journal of Medicine seemed to indicate that it may be beneficial in keeping weight off.
Entitled “Diets with High or Low Protein Content and Glycemic Index for Weight-Loss Maintenance”, this study was published on Nov 25, 2010. 773 patients were randomized after a 10% weight loss to 4 different groups of high or low protein and high or low glycemic index. Three of the 4 groups started immediately to regain the weight. The only group that successfully maintained the weight loss was the high protein, low glycemic index group. This was looking very good for The Atkins believers.
In 2005, in the Annals of Internal Medicine, the article “Effect of a Low-Carbohydrate Diet on Appetite, Blood Glucose Levels, and Insulin Resistance in Obese Patients with Type 2 Diabetes” showed that 2 weeks of a very low carbohydrate diet with no caloric restrictions reduced appetite and body weight. Dr. Boden writes,
“When we took away the carbohydrates, the patients spontaneously reduced their daily energy consumption by 1,000 calories a day”
Insulin levels dropped and insulin sensitivity was restored. Great!
Dr. David Ludwig added fuel to the fire in 2012 when he published his article “Effects of Dietary Composition on Energy Expenditure During Weight-Loss Maintenance” in 2012 in the Journal of the American Medical Association. Studying the difference in Total Energy Expenditure (calories burned) after weight loss, he found that the greatest decrease in TEE was the low-fat diet. The best? The very low carbohydrate diet. The implication here is that the very low carb diet will keep the metabolism higher and thus promote weight loss. Long live the revolution!
One of the first thoughts was that refined carbohydrates often lead to ‘food addictions’. There are satiety signals in the body for protein and fat. Hormones such as CCK and peptide YY respond to ingested proteins and fats to signal the body that we are full. Consider the last time you ate a buffet and could not eat any more. Now, think about eating another 2 pork chops. Ugh. Probably couldn’t do it. That’s the satiety hormones working.
But what if you were offered a small scoop of ice cream and apple pie? Doesn’t seem so hard to eat, does it? Some people in my family used to call the the ‘second stomach’ phenomenon. That is, after the first stomach was full, we imagined that there was a second stomach for desserts.
Think about foods that people say they’re ‘addicted’ to. Pasta, bread, cookies, chocolate, chips. Notice anything? All of these are highly refined carbohydrates. Does anybody ever say they are ‘addicted’ to fish? Apples? Beef? Spinach? Not likely.
Consider some typical comfort foods. Mac and cheese. Pasta. Ice Cream. Apple Pie. Mashed Potatoes. Pancakes. Notice anything? All of these are highly refined carbohydrates. Refined carbohydrates are easy to become ‘addicted’ and overeat precisely because there are no natural satiety hormones. The reason, of course, is that refined carbohydrates are not natural foods, but highly processed. The toxicity lies in the processing.
There were objectors, of course. One of the main concerns was that much of the initial weight loss seen in the Atkins diet was water weight. This certainly seems to be true. One of the prime objectives of the diet is to lower insulin levels by controlling carbohydrate intake.
One of the well known effects of insulin is to stimulate retention of salt and water. Specifically, insulin act on the proximal tubule in the kidney to stimulate reabsorption of sodium. So a diet that reduces insulin levels by severely restricting carbohydrates should result in salt and water loss. Since water is relatively heavy, a large proportion of the initial weight loss with the Atkins diet is likely, in fact water. Why is this a bad thing? I mean, who wants big swollen oedematous ankles? Cankles (calf+ankle) – me no like.
Excess salt and water retention will also lead to high blood pressure, so the loss of water weight seems like a very good thing to me. So why are the critics always hammering on this point?
Another commonly heard refrain that make no sense is that carbohydrate reduced diets are ‘nutritionally unbalanced’. This also makes no sense to me either. There are essential fatty acids. These are fats that our bodies cannot produce ourselves. Therefore, we are dependent upon our diet to provide these essential fatty acids to survive. Omega 3’s and omega 6’s are examples of these.
There are also essential amino acids. These are protein building blocks that humans cannot produce ourselves. Therefore, we are dependent upon our diet to provide these essential amino acids to survive. Phenyalanine, valine, and threonine are examples of essential amino acids.
There are no essential carbohydrates. They are not required for survival. Carbohydrates are essentially chains of sugars. There is nothing inherently nutritious about them. Many plant foods that contain carbohydrates (kale, broccoli) contain vitamins, minerals and other beneficial substances. But the carbohydrate itself is not essential or healthy. If we eliminate refined grains, this should leave us more room to eat nutritious things in our diet. So, why on earth would anybody in their right mind recommend eating a diet with 25% nutritionally bankrupt, addictive refined grains?
Another commonly heard issue is that high protein diets are bad for the kidneys. First, a carbohydrate reduced diet may be higher in either protein or fat, so it is not necessarily true.
A high protein diet may not be recommended for those with kidney problems. As a nephrologist, I specialize in kidney disease. In Chronic Kidney Disease, the ability to deal with the breakdown products of proteins is impaired and a high protein diet would not be recommended. However, in those with normal kidney function, there are no concerns. Several recent studies have looked at this specific concern. In the paper “Comparative Effects of Low-Carbohydrate High-Protein Versus Low-Fat Diets on the Kidney – Friedman et al, Clin J Am SocNephrol 7: 1103-1111; 2012″ healthy obese subjects were examined specifically for a detrimental effect on the kidney. The bottom line was there was not such problems. They write that a high protein diet “was not associated with noticeably harmful effects on GFR, albuminuria, or fluid and electrolyte balance”.
For many health reasons, losing weight is important. It can improve your blood sugars, blood pressure and metabolic health, lowering your risk of heart disease, stroke and cancer. But it’s not easy. That’s where we can help.