I do CrossFit and want to lose fat and build muscle. A dietitian said I need to eat more carbs.

• A 34-year-old man submitted an average day of eating to be reviewed for Insider's Nutrition Clinic.
• He told Insider he does weightlifting or CrossFit five times a week, and his goal is body recomposition.
• A dietitian recommends eating more carbs to fuel high intensity workouts.
• If you'd like to have your diet reviewed by an expert, fill out this form.

Sam, 34, submitted his eating routine for Insider's Nutrition Clinic, where qualified dietitians offer advice on readers' eating habits.

He told Insider his goals are having more energy, better endurance, and body recomposition. He does weightlifting or CrossFit at least five days a week.

"I attempt a 16-hour fast and consume approximately 2,600-3,000 calories a day," Sam said. "I'm 208lbs and approximately 20% body fat."

Sports dietitian and nutrition coach to professional CrossFit athletes Dr Mike Molloy told Insider that Sam's diet isn't bad, but he'd likely benefit from eating more carbs.

Sam has a high-fat late breakfast

After fasting for 16 hours, Sam has a late breakfast of four eggs cooked in butter with a high fiber tortilla, and coffee with butter, heavy cream, Stevia, and MCT oil.

Experts say fasting only leads to weight loss because it helps people stick to a calorie deficit, which can be achieved without fasting, too.

Molloy recommends Sam eat more carbs to boost endurance and energy.

"His diet is focused heavily around fats, with very few carbohydrates," Molloy said. "This is a problem because the vast majority of Sam's training appears to be high intensity through CrossFit."

The high intensity nature of CrossFit workouts taps heavily into the anaerobic system, which runs off glucose, a sugar molecule derived (mostly) from dietary carbohydrates, Molloy said.

The aerobic energy system, used for longer duration movements can rely pretty heavily on carbs too, Molloy said.

"Since Sam is training with high intensity, he would be better off to increase his intake of carbs, especially around his workout," Molloy said.

Not eating enough carbs can hinder workout performance and recovery, and also lead to flu-like symptoms.

Sam has meat and veggies for dinner

For his second and final meal of the day, Sam has a protein source such as steak, chicken, pork, or fish with high fiber vegetables like broccoli, cauliflower, or asparagus, and unsweetened almond milk.

Molloy said it's great that Sam is eating lots of micronutrient-dense veggies and protein.

"While we don't know the exact numbers, I would guess he is in the range of 0.75-1g of protein per pound of body weight. This is exactly where we want to be," Molloy said.

If Sam was willing to track macronutrients, Molloy recommends sticking to the 2,600-3,000 calorie per day range, but breaking down those calories into a ratio of 30% protein, 30% fat, 40% carbs.

"The overall intake of 2,600-3,000 calories per day is right around Sam's weight-maintenance range," Molloy said. "Assuming he's doing this seven days a week, he is for sure supporting his overall fitness-based goals."