How Can Irregular Mealtimes Affect You?

Did you know that eating and dining early is associated with a lower risk of becoming overweight? There are other effects derived from a modification of the schedules that we will comment on.
How Can Irregular Mealtimes Affect You?
Saúl Sánchez

Written and verified by el nutricionista Saúl Sánchez.

Last update: 09 July, 2023

Chronobiology is a branch of science that has been gaining interest in recent years. It studies how meal times affect nutrient metabolism and availability. Depending on the time of ingestion, different results could be obtained in terms of physiological processes, which, in turn, can have positive (or negative) effects on our health. Find out about the effects of irregular mealtimes.

Although there is still much to discover in this regard, very impressive advances have already been made. However, not everyone responds the same to changes in schedules as there’s an important genetic predisposition. Having said that, many people benefit from these modifications.

Eating early improves weight loss

According to a study published in the journal Nutrients, eating an early lunch and dinner is associated with a lower risk of being overweight. According to tests, most people who eat their midday meal before 1 p.m. and those who eat dinner before sunset tend to have better body composition status. This reduces the risk of getting ill in the medium term.

It is estimated that around 50% of the population benefits from this change in meal times. It’s likely that there’s a genetic polymorphism that can determine the response to this change, although it’s still difficult to identify. It would be necessary to carry out a study of genetic material that’s expensive and impractical these days.

However, eating earlier can have some positive effects on almost everyone’s metabolism. Due to a question of hormonal production, the body becomes more efficient in its metabolic tasks when fixed feeding schedules are maintained. In addition, it should be noted that eating food at night should be avoided, something that we will discuss in detail later.

However, it isn’t only important to have lunch and dinner early to achieve significant weight loss, but it’s also necessary to achieve a healthier diet. It’s essential to prioritize the consumption of fresh food in your diet, reducing the presence of industrial ultra-processed products. These contain simple sugars, trans fats and additives that are harmful to the body.

The Nutrients study also succeeded in showing that people who had lunch and dinner early had a more stable biological clock. They even had greater insulin sensitivity and metabolic flexibility, two parameters closely related to health. A positive effect could even be generated as regards lipid profiles, although more solid evidence on this is lacking.

Irregular mealtimes: it’s essential to avoid eating at night

Meal times depend on what the person is looking for.
During the night, nutrients are more likely to experience digestion and processing difficulties, so fat accumulation is favored.

Another aspect that chronobiology emphasizes has to do with the importance of avoiding food consumption at night. Until a few years ago it was said that sugars only had to be avoided once the sun had set. The body has a lower capacity to metabolize them and to use them precisely at this time of day.

It only makes sense to include these nutrients in your diet at night if you exercise beforehand. In this case, the carbohydrates are aimed at replenishing depleted glycogen stores, something that can determine performance in subsequent training sessions. You can even reduce the risk of injury with such a strategy.

However, in the rest of the scenarios, the consumption of simple sugars after sunset is counterproductive. In addition, in recent years it has been suggested that any consumption of food at night could alter the proper functioning of the biological clock. It would not only affect the metabolic capacity and the state of body composition, but also the subsequent rest.

In fact, as research published in the journal Chronobiology International states, avoiding eating at night when working shifts could limit the negative effects of poor sleep and altered circadian rhythms. Although this is an extreme scenario, anyone with normal habits could improve health by limiting food intake at night.

Even so, it should be noted that there are some nutritional strategies that can be put into practice at this time of day with positive effects on body composition. The most notorious of all of them has to do with the administration of a casein supplement during the moments before sleep. In this case, the recovery of athletes and endogenous protein synthesis at night are improved.

The body benefits by maintaining the same meal times

Although we have mentioned that eating earlier creates a significant benefit on health in the medium term, it must also be borne in mind that it’s crucial to avoid changes in routines from one day to the next. It’s best to establish a time for lunch and another for dinner and keep it consistent over time.

When many changes are made, imbalances can be experienced in hormonal production and in the body’s biological clock. Changes in the synthesis of certain hormones determines the body’s response to nutrients, as well as their subsequent use. This can lead to a greater tendency to gain fat weight, and difficulty experiencing muscle hypertrophy.

After all, humans are creatures of customs and habits. It’s best to plan healthy routines and alter them as little as possible during the day, avoiding irregular mealtimes. In this way, the body will get used to them and become more and more efficient in carrying them out, which prevents the development of complex pathologies in the medium and long term.

The only context in which it isn’t good to always follow a routine is in the case of physical exercise. Here it’s a positive move to ring the changes, especially in the weights you handle. Preventing the muscles and the nervous system from accommodating will cause greater adaptations, which will have a positive impact on metabolic and physiological parameters.

This is the only way to achieve a consistent change in body composition. Once the muscular adaptations are created, the hypertrophy processes are paralyzed, something that isn’t positive in the medium term. In addition, if the physical work routines are always identical, the body will need less and less energy to complete them, which will have a negative impact on the caloric balance.

How irregular meal times affect night workers

People who work shifts tend to be in poorer health than those who only work during the day. This is because their sleep rhythms are altered, which conditions the functioning of the biological clock. To this must be added a lack of control in the timing of meals, which ends up causing metabolic alterations and the development of type 2 diabetes.

First of all, it’s essential to avoid consuming simple and ultra-processed sugars at night. You should also restrict sugary sodas and limit caffeine. Simple carbohydrates ingested at this time have proven to be very harmful to the body, much more than those that appear in the diet in the morning.

The key is in the synthesis of melatonin

All those who stay awake during the night or who fall asleep late usually experience changes in the secretion of melatonin. This hormone is responsible for modulating the sleep and wake cycles, as well as the body’s circadian rhythms. In recent years it has been suggested that problems in the endogenous production of the substance could increase the risk of becoming ill.

It seems clear to state that defects in the synthesis of melatonin can affect the functioning of the central nervous system. However, the most current evidence manages to relate this situation to problems at the metabolic level. Also with a negative change in terms of body composition. For this reason, it’s advisable to ensure a good night’s sleep.

In some cases, it is very difficult to get a person to sleep at night, due to work habits. However, most people experience a significant improvement in their sense of well-being by modifying their schedules and including a melatonin supplement in their usual diet. This is evidenced by an investigation published in the journal Neurological Research.

It has even been shown that supplementation with melatonin could also be beneficial for the prevention of certain types of cancer. It also makes sense as an adjunct to anti-tumor pharmacology. However, in the latter case it’s essential to first have the approval of the specialist, since it isn’t feasible in all cases.

Does the timing of protein consumption matter?

Another issue related to chronobiology that has been discussed a lot in recent years is the effect of proteins after exercising. For some time it was claimed that taking a supplement of these nutrients right after finishing training was able to improve recovery markers.

For this reason, the hour after the end of the activity was categorized as an “anabolic window”, an ideal occasion to provide quality nutrients. However, the latest research claims otherwise. According to the latest findings, what matters is to cover the daily recommendations regarding protein consumption, not the specific moment of its intake.

Not even in high-level athletes are there significant differences in recovery or hypertrophy between taking the supplement before and after the work session. Of course, as far as the restoration of glycogen levels is concerned, there are significant changes.

According to research published in the Journal of the International Society of Sports Nutrition , it is preferable to consume a certain amount of carbohydrates in combination with proteins of high biological value in the moments after training to replace lost glycogen. This improves recovery from anaerobic efforts. The risk of fiber breakage is also reduced.

However, we’re talking about a very specific situation. In the rest of the cases, the moment of protein intake isn’t important. Only the exception of the casein already mentioned would be saved. Really the determining factor is to achieve the daily requirements, something that very few people are capable of. Most of the diets proposed are deficient in quality proteins and amino acids.

Can you eat fruit at night?

Now we come to the classic question “Can you eat fruit at night?”. To this day, it still generates great debate in the scientific community, although chronobiology seems to have quite a clear answer. It’s best to avoid eating these foods when the sun goes down.

According to the evidence reflected, the sugars consumed at night generate negative alterations on the metabolism. In this sense, it should be noted that fruit has a high concentration of fructose. Although the fiber modulates its absorption, the impact is significant. Also keep in mind that some varieties have more carbohydrates than others.

For this reason, it’s best to avoid eating fruit once the sun goes down. What’s more, some specialists recommend that these foods are not consumed in isolation. This means that the best context for including fruit in the diet is after one of the main meals.

In this case, the protein, fiber and fat content will modulate the absorption of fructose, generating a reduction in its impact at the pancreatic level. The elevation of glucose in the blood will be less and the work of the organ to synthesize insulin also, which will reduce the inflammatory stress within the organism.

Even the combination of fruit with a dairy product such as yogurt can be especially beneficial. In this case, the probiotic compounds of the fermentation are used and the prebiotics provided by the vegetable are added to them. Some of the fibers in the fruit, such as the pectins in apples, stimulate the growth of bacteria in the microbiota.

What about the consumption of supplements?

Meal times also include supplements
The schedules for taking supplements depend on the type of substance and the purpose of its consumption.

In the same way that there are certain ideal times for the consumption of food, dietary supplements shouldn’t just be taken at any time of the day. Its effects may vary if the dosage is altered. In some cases, it can even be dangerous to take any of these products at the wrong time, such as melatonin. It is not advisable to take it before driving.

For this reason, it’s important to always consult a specialist before including supplements in your regular routine. This won’t only confirm that they’re accurate, but it will also indicate what type of product to take, when and in what proportion. All these factors can have a decisive influence on the result obtained, changing the state of health for better or for worse.

For example, in the case of sports supplements we can distinguish between products that are consumed before sport and those that are ingested afterwards. Creatine is one of those that is always taken a posteriori, to recharge the deposits consumed. The same happens with branched-chain amino acids or with leucine.

However, caffeine, beta-alanine, or nitrates must be taken beforehand. With alkaloids, it’s also advisable to be careful, as it can also modify the biological clock and alter the body’s circadian rhythms. As a general rule, it’s advisable not to ingest caffeine after 6 in the afternoon so as not to interfere with the ability to sleep at night.

Schedules and intermittent fasting

Another of the fashionable dietary protocols that’s based on modifying meal times is intermittent fasting. It’s used primarily to improve body composition, although it also has benefits at the metabolic level. It’s even positive for athletes who want to increase the efficiency of the fat oxidation process to obtain energy.

In this case, what is achieved is a restriction in energy consumption for a period of not less than 16 hours. Normally, the limitation usually coincides with nighttime hours, in order to take advantage of the positive effects of the stabilization of the biological clock and of the normalization of circadian cycles. The protocol is extended until noon. From this moment on, feeding is allowed again.

Despite the fact that it’s a mechanism that has certain limitations, it tends to work well in a high percentage of the population. In addition, the side effects or risks are very limited, since the body is perfectly prepared to spend a certain time without a supply of nutrients or energy.

You should only be careful in the case of diabetics. Although intermittent fasting can benefit you, it’s important for the process to be supervised by a professional. Pregnant women, infants and children, and adolescents shouldn’t adhere to this type of feeding protocol, as they generally need a higher supply of nutrients.

However, despite the benefits of including an intermittent fasting protocol by modifying the schedule of meals, it’s essential to ensure the approach of a varied and balanced diet. Always ensure that essential nutrient requirements are met. A deficit could increase the risk of developing health problems in the medium term.

Meal times and diabetic patients

To conclude this topic related to chronobiology, we must talk about how meal times influence the management of blood glucose in diabetic patients. The truth is that the latest research has reflected great advances. Modifying eating habits and timing may help control blood glucose levels, which improves the well-being of people with diabetes.

In the first place, it must be taken into account that dining late is again associated with a worse state of health. According to a study published in the journal Cureus, a lack of control over blood glucose is experienced from this habit. However, there is more disagreement with the issue of breakfasts.

On the one hand, the articles that talk about intermittent fasting tell about the benefits of the practice in the case of a person with metabolic pathologies. However, it’s also possible to find trials that refer to an improvement in the physiological parameters related to diabetes when a healthy breakfast is considered.

In this sense, it seems that there are several strategies that could be put in place for the treatment of diabetes. All of them can generate positive effects, so it’s key to choose the one that causes the highest level of adherence in the person. Of course, what all the trials agree on is that having lunch and dinner earlier is beneficial for these patients.

Meal times influence health

Correctly managing the meal schedule can protect against the development of many chronic and complex diseases. The body doesn’t respond the same to the intake of nutrients throughout the day. The circadian production of hormones and the biological clock have a lot to say about this.

In any case, a healthy diet is always recommended. Likewise, other appropriate habits such as the practice of physical exercise on a regular basis should be promoted. Prioritizing resistance exercise generates an indisputable benefit on the levels of health and well-being.

Finally, special mention must be made of the need to get a good night’s rest. As far as possible, it is necessary to ensure that they sleep 7 or 8 hours a day, always at night. Otherwise, the physiology could be negatively altered, generating inefficiencies.

  • Lopez-Minguez, J., Gómez-Abellán, P., & Garaulet, M. (2019). Timing of Breakfast, Lunch, and Dinner. Effects on Obesity and Metabolic Risk. Nutrients11(11), 2624.
  • Grant, C. L., Coates, A. M., Dorrian, J., Kennaway, D. J., Wittert, G. A., Heilbronn, L. K., Pajcin, M., Della Vedova, C., Gupta, C. C., & Banks, S. (2017). Timing of food intake during simulated night shift impacts glucose metabolism: A controlled study. Chronobiology international34(8), 1003–1013.
  • Aarrebo Jensen, M., Hansen, Å. M., Sallerup, M., Odgaard Nielsen, N., Schlünssen, V., & Helene Garde, A. (2020). Acute effects of night work and meals on blood glucose levels. Chronobiology international37(9-10), 1384–1391.
  • Xie, Z., Chen, F., Li, W. A., Geng, X., Li, C., Meng, X., Feng, Y., Liu, W., & Yu, F. (2017). A review of sleep disorders and melatonin. Neurological research39(6), 559–565.
  • Li, Y., Li, S., Zhou, Y., Meng, X., Zhang, J. J., Xu, D. P., & Li, H. B. (2017). Melatonin for the prevention and treatment of cancer. Oncotarget8(24), 39896–39921.
  • Kerksick, C. M., Arent, S., Schoenfeld, B. J., Stout, J. R., Campbell, B., Wilborn, C. D., Taylor, L., Kalman, D., Smith-Ryan, A. E., Kreider, R. B., Willoughby, D., Arciero, P. J., VanDusseldorp, T. A., Ormsbee, M. J., Wildman, R., Greenwood, M., Ziegenfuss, T. N., Aragon, A. A., & Antonio, J. (2017). International society of sports nutrition position stand: nutrient timing. Journal of the International Society of Sports Nutrition14, 33.
  • Mirghani H. (2021). The Effect of Breakfast Skipping and Late Night Eating on Body Mass Index and Glycemic Control Among Patients With Type 2 Diabetes Mellitus. Cureus13(6), e15853.

Este texto se ofrece únicamente con propósitos informativos y no reemplaza la consulta con un profesional. Ante dudas, consulta a tu especialista.