You have been told to not have your dinner too late, beyond a certain timepoint, because you will get fat easily if you do that.
So, does it also mean that I won’t get fat easily no matter what as long as I eat before a certain timepoint?
How does meal timing relate with weight management?
Recent hypotheses propose that meal timing plays a role in weight regulation through mechanism of circadian rhythm, a fancy term for body clock. It is suggested that nocturnal eating (eating late in the evening) may result in metabolic disruption, as in hormonal and enzymatic expression that affect nutritional metabolism. These metabolic disruptions are proposed to be one of the reasons metabolic abnormalities are observed in individuals with nocturnal feeding habits.
Other than physiological reasons, foods consumed in the evening also tend to be more energy dense or larger in amount due to reasons such as increased hunger, food availability or social activity. A simple example would be heightened subjective perception of hunger after work due to stress that consequently causes overeating. However, there is little evidence to support these hypotheses.
What do scientific evidences suggest?
A comprehensive meta-analysis suggests that recommendations to reduce evening intake is not substantiated by clinical evidences in totality. There are, however, certain longitudinal studies and scientific articles that suggest consumption of food during late evening plays an important role in body composition or is associated with metabolic syndrome. However, it is important to note that in non-randomized controlled trials like these, possibility of reverse causality cannot be neglected. Meaning, instead of saying that late eating caused higher rate of obesity, it might also be that obese people tend to eat late evening.
What is important in weight management?
Priority of nutrition-related factors are listed in ascending order
- Energy balance (Most important determinant in weight changes)
- Macronutrient distribution (Important determinant of body composition changes)
- Micronutrients, Dietary Fibre Content
- Dietary quality factors (Glycaemic index, Protein quality/bioavailability, Antioxidants)
- Meal timing (distribution of meals, increased nutrient availability through coupling such as vitamin C + iron)
So… is meal timing important or not?
It is a very complex question to give a binary answer with.
The answer is it depends… Depends on what?
- Your overall daily energy intake
Considering that the principle of energy balance is the main determinant of weight changes, the primary concern should be the management of your total daily energy intake. Furthermore, studies that support an association between meal timing and unfavourable weight changes also explained that night-time eaters eat more per day. This suggests that the larger total amount of food consumed daily is the root cause, whilst meal timing is just an indirect factor.
- What foods you eat late?
Different types of food differ in nutrient value. Night-time consumption of small (150 kcal) single nutrients or mixed meals are not harmful and may even promote greater muscle protein synthesis and cardiometabolic health, as suggested by an article.
So… does meal timing matter?
From an evidence-based perspective… scientific evidences remain too inconsistent to substantiate a full-fledged recommendation to prevent late night eating habits…
From a physiological perspective… scientific evidences on disrupted metabolism at night remain too inconclusive and novel to suggest eating at night will increase tendency of body to store fats…
From a behavioural perspective… depending on your food availability, food choices, eating behaviour (tendency to overeat due to stress/increased hunger) and others, meal timing MAY influence your weight management efforts through indirect factors… and hence trying to avoid having large, unhealthy meals at night can contribute to better weight control.