Dr. Reeta Achari is a neurologist who's found many patients with symptoms including numbness, dizziness and confusion. They come to her fearing a nervous system illness, only to find out they have vitamin deficiencies.
"I've discovered a lot of people are eating very restrictive diets," Achari said. "The brain fog issue became very common with the gluten-free diet."
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She said one young female patient's diet was so restrictive it led to a scurvy diagnosis. The vitamin C deficiency is more often associated with pirates and sailors from a hundred years ago than modern medicine. Achari said the woman ate no fresh fruits and vegetables, just soup.
"She only ate canned soup. It was chicken tortilla soup. And it was a very busy young lady," Achari said.
Many people have tried crash diets and unorthodox fixes. One recent weight loss success story, Harold Henson, said he finally found success when he started working with a nutritionist and trainer at Timberline Fitness in Houston.
"A lot of that was not healthy food," Henson said. "I decided for the long term, I'd do the weight loss first and do it slowly and gradually."
He worked with nutritionist Jennifer Theriot at Timberline. She said one-size-fits all fad diets just don't work.
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"It's important to eat a variety of food to get all the nutrients you need."
Theriot uses a metabolic test to help give clients a baseline for their calorie needs and then helps set up a nutrition plan with balanced macronutrients -- fats, protein and carbohydrates. She also makes sure their vitamin and mineral needs are met by including plenty of vegetables and fresh foods. Trainers help tailor workout plans to each client.
"The best thing you can do is have a healthy proportion," Theriot said.
Dr. Achari agrees, saying she's been able to help many patients by adapting what they eat.
"In the last five years, I've given out more recipes than drugs," she said.
As for some of the popular diets, like the Paleo diet and gluten-free diets, Achari said they can be done in a healthy way, but they are often problematic.
"The Paleo diet has been interesting because people are eating proteins and greens, which is great. Unfortunately, if the only thing that you're eating in your Paleo diet is grilled chicken breasts and broccoli, that's no very good for you."
Of gluten-free diets, Achari said many people cut out all wheat products and, in doing so, lose many sources of B-vitamins. She said human diets have adapted well to eating whole grain wheat and that is often part of a healthy diet.