I want to lose fat and build strength. A dietitian said to eat more carbs and fat.

To lose fat while building strength, it's important to eat enough food, including carbs and fat, a dietitian said.

• A 29-year-old man submitted an average day of eating to be reviewed for Insider's Nutrition Clinic.
• A dietitian said to eat more carbs and fats to support his high activity levels.
• If you'd like to have your diet reviewed by an expert, fill out this form.

Ian, 29, submitted his eating routine to Insider's Nutrition Clinic, where qualified dietitians and registered nutritionists offer advice on readers' eating habits.

He told Business Insider that his goals are to lose fat and build strength. Ian said: "I don't need to look big, but I do want my muscles to be dense and strong and have a nice aesthetic. I signed up for my first sprint triathlon in June, which I'd like to win in my age group."

Ian weighed 200 pounds on February 1 and decided to start going to the gym every weekday, and twice a day every other week. Every Wednesday, he focuses on active recovery, rest, rehab, and stretching, and only goes to the gym in the morning, but sometimes does some light activity in the evening if he's bored, he said.

Every weekday, Ian walks 2 to 2.5 miles on his lunch break. On weekends, he has another active recovery day when he swims laps, walks at an incline on a treadmill, or cycles on a stationary bike. He often goes to water polo practice one evening a week and has started incorporating more running, swimming, and cycling into his workouts in preparation for the sprint triathlon, he said.

After reviewing Ian's diet, dietitian Jaclyn London told BI that it's great that Ian is eating lots of protein, but because of his extremely high activity levels, he would likely benefit from having more carbs and fats so he's getting enough calories — even if he wants to lose fat.

Ensuring he's resting enough will be key to hitting his goals too, London said.

Eat a substantial breakfast

Ian works out at 5 a.m. and has a protein shake with a scoop of greens powder after. He doesn't typically eat a big breakfast but usually has three or four strawberries with a tablespoon of non-fat Greek yogurt by 9 a.m., he said.

London said that it's important to eat protein after a workout to help muscles recover (as well as over the course of the day). She recommended blending the protein powder with 2% milk, a banana, and some nut butter for extra calories and nutrients.

For breakfast part two, London recommended a more substantial portion.

"I'd choose whole or 2% unsweetened Greek yogurt, which will maximize protein and provide some satiating dietary fat without excess calories from added sugar found in sweetened versions," she said.

London recommended topping it with more fruit, chopped nuts, and seeds to help Ian feel more satisfied, alert, and energized, and to fuel his training.

Eating a range of fruits and vegetables will help ensure Ian's body functions at its best, she said.

Don't avoid carbs

On most days, Ian eats the same meal-prepped lunch and dinner: grass-fed ground beef or bison cooked with bell peppers, onions, diced tomatoes, green chilies, spinach, and eggs.

"Sometimes I add brown rice but I tend to avoid carbs," Ian said. He adds a heaping scoop of fat-free Greek yogurt and a sprinkle of low-fat shredded Mexican blend cheese. Ian said he thinks his portions are probably a bit low on calories but he has been trying to lose fat.

London said it's great that this is a high-protein meal, and Greek yogurt is a smart high-protein swap for sour cream, but Ian needs more complex carbs.

"Adding half a baked or sweet potato to this mix would help Ian feel more energized, and will help with muscle recovery," she said. "Consuming carbs with protein is necessary, especially post-training since carbs help to act as a delivery system for amino acids to your muscle tissue."

Beans, lentils, chickpeas, and peas would also provide carbs as well as fiber and plant-based protein, she said.

Eat oily fish

When Ian isn't eating his meal-prepped beef, he's out socially one to three times most weeks. At home, he often has a protein shake with dinner.

London said Ian would likely benefit from adding some seafood to his diet.

"Yes, Ian will get omega-3 fatty acids from grass-fed beef, but the best source of these critical nutrients for muscle recovery and decreasing inflammation can be found in fatty fish," she said. Examples include salmon, tuna, white fish, black cod, bass, sardines, and mackerel.

London recommended that Ian slightly vary his meals, perhaps making a deconstructed burrito bowl or using different vegetables and serving with tacos or toast, to ensure he's consuming a variety of foods and nutrients.

"Unless he loves that protein shake, it may not be necessary every day once we've bulked up breakfast, lunch, and snacks to be a little more satisfying and to incorporate a source of protein," London said.

Snacks are an opportunity to eat fruit and vegetables

If he's hungry between lunch and dinner, Ian eats an RX protein bar. In the evening, he might eat a bag of microwave movie theater butter popcorn.

"That's the most unhealthy thing I eat, but I love popcorn," he said.

London said RX bars are a great choice because, as protein bars go, they're not too processed. However, she thinks Ian could benefit from snacking on more fruits and vegetables, even if that just means adding a banana to the RX bar.

"I'm all about snacks that provide a satiety-promoting trifecta: protein, fat, and fiber," London said. She also suggested trying peanut butter on whole-grain toast with fruit, or avocado on whole-grain toast with an egg on top.

In the evening, London said that Ian shouldn't fear some sugar and it could actually help his training. She suggests chocolate milk, DIY trail mix (mixed nuts, chocolate chips, and popcorn), or microwave-baked apples with nut butter and ice cream.

"All of these additions will help him add key nutrients including calcium, potassium, magnesium, fiber, and minerals, include a little bit of delicious sweetness for the sake of pure enjoyment, and won't derail his efforts for fat loss," London said.

Moving a lot requires eating a lot

London said it's important that Ian is hydrated as he ramps up his training, and he may benefit from adding some carb and electrolyte sachets to his water to help maintain his glycogen stores.

"I know athletes like Ian are often hesitant to use electrolyte powders that have added carbohydrates, but this ingredient inclusion is the only way these products actually work to help you stay both hydrated and energized during races, so don't shy away from using them," she said.

London's biggest concern about Ian's diet is that he's not eating enough to support his rigorous training regimen, even if fat loss is his goal.

"Top priority for Ian is to eat more, but include foods that are going to help him fuel his rigorous training schedule, feel more satiated and energized, and meet his goal of losing body fat over time," London said.

Ian would likely also benefit from more rest, taking at least one full rest day every week to allow his muscles to recover and ensuring he's sleeping for eight hours a night, London said.

Finally, she said swapping two cardio workouts for strength training would help Ian build muscle, strengthen him for the triathlon, and reduce injury risk from all his cardio.