Considering going on a weight loss diet? With the bounty of weight loss programs available, some new information has surfaced about the composition of weight loss diets and mood.

Researchers in Australia recently conducted a study to evaluate the effect dietary composition had on mood and behavior. One hundred six overweight/obese individuals whose average age was 50 were studied for a year. Participants were divided into two groups: 55 consumed a low carb high fat diet (4% carbohydrate, 35% protein, and 61% fat with 20% being saturated); 51 consumed a high carb low fat diet (46% carbohydrate, 24% protein, 30% fat, and 8% being saturated).

During the study, measurements included cognition, mood, anger-hostility, and depression. In the first two months, both groups lost weight (~ 30 lbs.) and experienced an increase in mood. No real secret there, eh?

The researchers noted that both groups followed a specific regimen which included counseling. However, as time progressed, those who consumed the low fat diet maintained a better state of mind versus those on the low carb diet who tended to be more negative.

A few reasons for such a difference were postulated by the researchers. Following a low carb diet may be difficult in the long term, especially for those on a Western type diet which includes more carbohydrates. Living with the type of structure a low carb regimen entails can be difficult to maintain, particularly in social situations. The low carb diet also had an effect on serotogenic functions in the brain. These functions have been associated with depression and anxiety. Conversely, a high carb diet can potentially increase serotonin synthesis.

Here’s what happens: Serotonin is manufactured in the brain and acts like a neurotransmitter. It is synthesized in the body by the amino acid tryptophan and the enzyme tryptophan hydroyxylase, which forms 5-hydroxytryptamine, also known as serotonin. Foods high in protein, such as beef, poultry, dairy, nuts, etc. contain higher levels of tryptophan. After an individual consumes a meal high in these proteins, the tryptophan levels actually drop. The reason is that tryptophan is an amino acid and competes with other amino acids to enter the brain. Consequently, only a small amount of tryptophan actually enters the brain, so serotonin levels do not increase.

However, when a higher carbohydrate meal is consumed, it causes the body to release insulin. What happens next, according to nutritionist Elizabeth Somer, is that with a rise in insulin, more amino acids are absorbed into the body, but not the brain. One exception is tryptophan, which remains elevated and therefore can enter the brain and increase serotonin levels. Another key to help open the door to serotonin synthesis is an adequate supply of vitamin B6, (found in chicken, fish, pork, liver, kidney, whole grains, legumes, and nuts).

So, in summary, if you want to be a little “happier” while reducing your caloric intake, consuming a higher quantity of complex carbohydrates would likely be the ticket. Complex carbs include grains, pasta, rice, fruits, and vegetables. Additionally, carbohydrates provide quick and sustained energy, along with fiber, which improves digestion and satiety. Eating a balance of protein, carbohydrate and fat at meals and snack time can keep blood sugar steady (which also regulates hunger and mood), and improves nutrient absorption.

Some snack examples include:
-Half sandwich
-Fruit, veggies or crackers with cheese, cottage cheese, hummus or nut butter
-Bowl of cereal
-Unsweetened yogurt with cereal, nuts, and fresh or dried fruit
-A small salad with greens, veggies, beans and vinegar with a drizzle of olive or canola oil
-A small taco or quesadilla
-Steamed pork dumplings
-Chocolate milk

Author's Bio: 

Susan Piergeorge is a Registered Dietitian. Her background includes nutrition consulting, health promotion, food manufacturing and culinary experience. Her blog is