THE BLOG
12/01/2014 04:27 pm ET Updated Jan 31, 2015

Are Carbs Evil?

Olivia Bell Photography via Getty Images

Can you believe just a few decades ago, fat-free foods were the rage? I remember one evening, a very fit friend offered huge bowls of jelly beans and pretzels to our group as an evening snack. She was so happy that these foods were 'perfectly healthy' because they were fat-free.

Today, people are much more wary of carbohydrates than fats. A few months ago, I was hanging out one evening with a different group of health-conscious friends. The evening treat of choice today is bacon and chocolate. Is this progress or a new fad?
I think a few points are indisputable:

• Sugar and processed carbs can ruin our weight and our health.
• The human body can subsist without carbs.
• Some of the best parts of our diet, like green veggies and seafood, do not have carbs.

For starters, let's look at the relationship between carbohydrate intake and the recent obesity crisis. From 1971 to the year 2000, the intake of carbs has increased for both men and women. Starting in the mid-1980s, obesity started increasing at unprecedented rates. Many said this correlation was clear evidence that carbs are to blame. However, during the same timeframe, the intake of fat and protein also went up. Furthermore, in the 1970's and before, people were much leaner, yet men and women still got many more calories from carbs than from fats or proteins. When people were leaner, carbs made up 42 to 45 percent of their daily calories.

If the carbs were the sole cause of weight gain, then we should also see the people on low-carb diets lose more weight than those on high or moderate carb diets. A pivotal study, published in 2009, answered this very question. In the study, 800 dieters were placed in four equal groups. For two years, one group ate a low carb diet, one ate a high carb diet, and the last two groups ate diets with different levels of moderate carbs. The intake of carbohydrate ranged between a 35-percent low-carb diet up to a 65 percent very high-carb diet. If carbs were the culprit, the groups eating less should have lost the most. Yet, at six months, 12 months, 18 months and 24 months, all groups had an identical amount of weight loss, waist circumference loss and fat loss.

Even if carbs are not the clear suspects behind obesity, why not eat less to be sure? Is it bad to eat too few carbs? Studies have shown if you have too few carbs, you can end up with insomnia, fatigue and depression. Why would low-carb diets cause insomnia? We sleep when our bodies make a neurotransmitter, called melatonin. Melatonin is made out of the amino acid tryptophan. When we eat carbs, all of the other amino acids, besides tryptophan, are pulled out of your bloodstream. Freeing up the competition, helps tryptophan enter your brain and make melatonin. Diets that are too low in quality protein, provide too little tryptophan. Diets that are too low in carbs, keep tryptophan from getting into your brain.

This same lack of melatonin is associated with too little of a mood-enhancing chemical, called serotonin. If we have too little serotonin, we are more apt to feel depressed and anxious. Most of the medications used to treat depression are thought to work because they raise serotonin levels. Carbs raise serotonin and can reduce feelings of depression.

Have you ever worked out really hard and felt really awful afterwards? Studies have shown that exercisers who do not get enough carbs will feel more stressed and tired for longer periods of time.

Please know that just because we do eat some carbs, a loaf of Wonder Bread each day is not the answer! Look for the next installment on this article as we cover the three rules of carbs: the best types of carbs, the best amounts and the best times of day to eat them.