6 days ago
Should Breakfast, Lunch or Dinner Be Your Biggest Meal? Dietitian Reveals the Answer
You've probably heard saying that "breakfast is the most important meal of the day." While there are certainly benefits to starting your morning with a nutritious meal, some people may find it difficult to stomach food after waking up.
Maybe you prefer eating a big lunch to break up the workday, or you feel like you need a heavy dinner to fall asleep.
Meal timing is highly personal and cultural. Not everyone follows the standard three-meal Western diet: breakfast by 9 a.m., lunch around noon and dinner between 5–8 p.m. But if you do use this eating pattern, you may have wondered which meal should be the biggest.
The timing and size of meals does matter — there's even an emerging field dedicated to studying how this affects our health.
"Chrononutrition" is the science of how meal timing, the body's 24-hour internal clock (aka circadian rhythm) and metabolism interact, Collin Popp, Ph.D., dietitian and assistant professor in the department of population health at the NYU Grossman School of Medicine, tells
When you eat — and how much — can impact energy levels, metabolic health, weight, blood sugar and more.
So, which meal should be the highest in calories? What about the timing of eating protein, carbohydrates and fats?
What Should Be Your Largest Meal of the Day?
'Typically, I advise people to try to eat most of their calories earlier in the day,' says Popp. Ideally, breakfast or lunch should be the largest meals, calorie-wise.
"Breakfast doesn't necessarily need to be the biggest, but if you have a small breakfast, try to have a big lunch and a smaller dinner."
Even if you prefer to eat several meals throughout the day instead of three main ones, the goal is to shift your calorie intake earlier and avoid eating too late. This strategy is called 'front-loading' calories, says Popp, which has a number of potential benefits.
Benefits of a Eating a Large Breakfast or Lunch
Front-loading your calories may help improve daytime energy levels, align with your metabolism and aid with blood sugar control.
Our metabolism is the process by which our body breaks down food to use as energy, and the energy expended to do this, says Popp. 'We metabolize our food different from morning versus the evening. If I gave you the same meal at 8 a.m. and 8 p.m., your body has a different response because of our 24-hour clock."
We tend to have a greater metabolic response in the morning, Popp adds, so the body expends more energy to break down food.
Eating most of our calories during daylight hours instead of nighttime better aligns with our our body's circadian rhythm, which regulates sleep, he adds.
Front-loading calories can kick-start our body for the day. In the morning, our liver's glycogen stores are lower after fasting overnight. Eating a big breakfast replenishes those stores, so we feel more physically and mentally energized.
This strategy can also curb hunger and unhealthy cravings. In a 2017 study, researchers found that subjects who ate their largest meal at breakfast or lunch were more likely to lose weight than those who made dinner their largest meal.
Finally, eating earlier can be beneficial for blood sugar. 'Our bodies, especially the liver and muscles, which are great regulators of blood sugar, are more sensitive to hormones like insulin in the morning,' says Popp.
Downsides of Eating a Large Dinner
Eating a large dinner is not inherently unhealthy, but consistently getting the majority of your calories late in the day can have potential downsides, even if you eat healthy, according to Popp.
It may disrupt sleep because it interferes with our circadian rhythm or worsens indigestion, negatively impact blood sugar and contribute to weight gain.
'Eating late and eating too many calories after a certain period has been associated with diabetes and obesity," says Popp.
Research shows that eating the majority of calories later in the day is associated with a worse glucose tolerance. People with pre-diabetes or Type 2 diabetes may have a higher blood sugar the morning after eating a large dinner, Popp notes.
A small study published in Cell Metabolism in 2023 found that late eating can increase hunger the next day and decrease levels of the appetite-regulating hormone leptin, which may lead to higher calorie consumption and increase the risk of obesity.
"If you really want to eat later in the day, keep the meals smaller, balanced, and focus on nutritious, minimally processed foods," says Popp.
How to Time Protein, Carb and Fat Intake
In addition to meal timing, it's important to consider your intake of carbohydrates, protein and fats. 'It's not always about calories, but also what those meals made of,' says Popp.
Protein
Protein helps build muscles and keeps us feeling full, which can aid with weight management.
"It's best to distribute your protein evenly throughout the day," says Popp, but front-loading protein also has benefits. Eating a protein-rich breakfast can increase satiety throughout the day and help with blood sugar control and insulin resistance.
The recommended daily intake of protein is about 0.8 grams per kilogram of body weight for adults — for a 150-pound person, that's about 54 grams of protein per day. However, some people may need to follow a higher-protein diet.
High-quality protein options include eggs, beans, lean meats, fish, greek yogurt, tofu, lentils and nuts.
Carbohydrates
Carbohydrates are the body's main source of energy. While carbs can also be distributed throughout the day, Popp recommends trying to eat more carbs in the morning or midday, especially if you have an active lifestyle.
'We're more sensitive to those carbs in the morning, so we can better burn them for fuel or store them in our muscles as glycogen,' says Popp. It's also optimal load up on carbohydrates before exercise.
However, the type of carb matters. Popp cautions against highly processed, refined carbs, such as sugary cereals. Instead, opt for healthier complex carbohydrates, which take longer to digest, such as potatoes, oats, brown rice, bananas and chickpeas.
Fats
Fats provide long-lasting energy, help the body absorb vitamins, and support brain health.
Dietary guidelines recommend fats make up 20-35% of your daily calories, but not all fats are equal. Aim to eat more heart-healthy unsaturated fats, says Popp, and limit or avoid saturated and trans fats.
You can distribute healthy fats evenly throughout the day, but eating higher-fat meals earlier in the day may help with energy levels and satiety, Popp adds. Foods high in healthy fats include avocados, extra virgin olive oil, walnuts and salmon.
If you eat a higher-fat dinner, Popp recommends pairing it with physical activity after, such as a walk, which may help with digestion before bed.
Tips to Eat Earlier in the Day
What if you can't stomach breakfast, or even lunch? "I often hear people say they're just not hungry in the morning,' says Popp.
Many factors can inhibit hunger in the morning, but a major reason is eating too large of dinner or late snack, says Popp. As a result, you may wake up feeling full and skip breakfast or lunch, then keep shifting your calories later in the day. 'That cycle just repeats itself,' he adds.
If you're not a breakfast person but want to change your meal timing, Popp offers several tips.
When you wake up, have your favorite foods ready to go — whether it's yogurt, berries or hard-boiled eggs. "Try to eat something at breakfast, even if it's small," says Popp.
"Then, try to have a slightly earlier or bigger lunch than normal," and make sure you're getting enough protein, says Popp.
If you aren't able to eat breakfast or a big lunch, Popp suggests shifting your dinner earlier. "If you always eat dinner at 8 p.m., try to eat dinner at 5–6 p.m., and make it smaller," says Popp, adding that this may help "reset" your body so you feel hungry the next morning and can change your eating pattern.
Always talk to your doctor if you have questions.
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