November 3, 2026, 6:44 pm | Read time: 4 minutes
A hearty breakfast might help you feel less hungry throughout the day–but does it also lead to faster weight loss? This question is also a focus of research. For instance, scientists at the University of Aberdeen in Scotland examined a few years ago the difference it makes whether we consume most of our daily calories in the morning or evening.
In a study published in 2022, a research team led by Professor Alexandra Johnstone compared the effects of a large breakfast with those of a large dinner. The study involved 30 people with overweight or obesity. They were given a calorie-reduced diet, with most of their daily calories consumed either in the morning or evening.1
The result was that participants felt less hunger and appetite when they ate more in the morning. However, there was no significant difference in weight loss. Those who consumed most of their calories at breakfast did not lose noticeably more weight than those who ate more in the evening. Thus, a large breakfast can help reduce hunger throughout the day, but it doesn’t necessarily lead to faster weight loss.
Why the Timing of Meals Still Matters
Even if a large breakfast doesn’t automatically lead to more weight loss, it apparently makes a difference for our metabolism when we eat.
Dr. Sarah Chellappa, a chronobiologist at the University of Southampton in the UK, explained to BBC Science Focus that the human metabolism is designed to process nutrients efficiently during daylight hours and conserve energy at night.2
This is partly due to our internal clock, which follows a roughly 24-hour rhythm and influences not only sleep but also hormones and metabolism. Daylight plays an important role in regulating this rhythm. The extent to which the time of day can affect food processing is evident in blood sugar levels.
Losing Weight with a Hearty Breakfast Works—If It’s on the Plate
How a Good Breakfast Affects Our Body
Blood Sugar Can Rise More in the Evening
According to Chellappa, the same meal in the evening can cause an 18 to 46 percent higher increase in blood sugar than in the morning. The hormone insulin plays a role in this. It helps the body absorb sugar from the blood into the cells. However, insulin sensitivity decreases over the course of the day, which can result in more sugar remaining in the blood after an evening meal.
Scientific studies also show such differences. In a study published in 2015, blood sugar levels after a meal in the biological evening were about 17 percent higher than in the biological morning.3
Another study from 2019 also showed that the blood sugar response to a meal can depend on the time of day.4
But it’s not just blood sugar that changes. According to Chellappa, the body’s ability to break down and burn fat decreases by 10 to 20 percent overnight.
Also interesting: How a good breakfast affects our body
When Should You Eat the Largest Meal?
Based on insights into the internal clock, Chellappa recommends that the largest meal of the day should take place as early as possible, such as at breakfast or lunch. Dinner, on the other hand, should be smaller.
However, there is no fixed time after which eating becomes generally unhealthy. It also depends on when someone goes to sleep. Chellappa points to the recommendation from chronobiologists to avoid consuming additional calories at least three hours before bedtime.
Not everyone needs to follow the same eating rhythm. Work schedules, sleep habits, and personal daily routines can influence when meals are sensibly planned. Research thus highlights two different aspects: The body processes food differently depending on the time of day. At the same time, a larger breakfast can help reduce hunger later.
However, the study from the University of Aberdeen could not show that simply shifting calories to the morning results in more weight loss.