When it comes to weight loss everything is on the table as far as strategies go. Forks that beep when you eat, diet supplements, special plates, glasses that tint your lovely meal unappetizing colours… the list goes on.
One of the more studied interventions is the question of WHEN to eat. The evidence is pretty conclusive that the amount of food and to a lesser degree the types of foods you eat can impact weight gain or loss BUT does WHEN you eat matter? We aim to settle the meals vs. snacking and the morning vs night eating debate once and for all.
Meals vs. Snacking
Overweight and obesity are obviously linked to eating more calories and any dietary weight loss strategy aims to reduce the calories consumed. With respect to meal frequency, U.S. data comparing 1977 to 2006 shows an increase in snacking prevalence and contribution to the percent of total calories consumed – a whopping 24% by 2006 (1).
The problem is that most of the “snacks” were unhealthy sugar-, fat- and salt-laden treats not healthier low-calorie snacks like veggies (1). Perhaps more alarming is the increase in “snacking” on sugary drinks (2). Snacking on beverages is of particular concern because they have a relatively low satiety value – you can drink lots of calories and not feel full (3).
A study in lean and obese people found that whole foods – an apple vs. juice or apple sauce – was associated with lower hunger ratings. The time until their next meal was also longer if they ate the apple sauce or apple as compared to the juice. They also found that hunger was lower when the apple was consumed 2 hours after the meal than as part of the meal. However, there was no difference between when they ate the apple snack; either after the meal or a two hour delay with respect to when they ate their next meal (4).
A review of many studies notes that although several have found lower body fat with more frequent meals, this is likely due to inaccurate self-reporting of food intakes. Studies controlled by researchers, find either no difference or a slightly greater caloric intake with more frequent meals BUT, these studies are mostly short term (5). Longer controlled studies suggest that eating a snack does not cause people to eat less at meal time; thus, leads to an overall increase in calories, especially if the “snack” is a sugary drink (4,5).
Conversely, others suggest that eating three meals per day as opposed to two made people feel fuller and burn more fat even though they consumed to same amount of calories in each group (6). In all likelihood, it probably comes down to what people are snacking on rather than snack or not and how it impacts their overall calories for the day.
Time of Day
Does the time of day when people eat impact obesity and other metabolic factors associated with cardiovascular disease? People eat larger meals more frequently when they eat later during the day. People also feel less full after a meal as the day progresses. A study using 7-day food records in over 800 people found negative correlations between the proportion of food eaten in the morning and the overall intake; whereas, the opposite was seen in the evening. Morning eating makes you feel fuller and can reduce your energy intake as opposed to eating later in the day; however, the size of the correlation was small and correlation is not the same as causation (7).
Interestingly, the greater the energy density (more calories) of a food the more of the food people ate. Suggesting that the WHAT you eat is as important as or more so than the WHEN (7). Another study in mice found that when they ate a high fat diet at the time of day when they are the least active they weighed more than the mice that were fed during their active time of day (8). Studies in humans support this conclusion where it was found that “evening type” people had a less healthy diet, ate later, ate fewer but larger meals and had lower levels of the good cholesterol (9). Early eaters were also more successful in a weight loss intervention (10).
No Baloney’s advice. What you eat is definitely more important than when you eat. Once you’ve mastered the healthy diet, playing with your meal timing may help a little bit. Eating more of your food during the morning hours should increase fullness and consequently reduce your food intake throughout the day. As for snacking, avoid the sugary drinks and eat at least three meals per day. After that it all seems to come down to what you snack on and how it impacts your total calories for the day.
Choose solid foods to snack and be aware that if you snack you need to eat less at your big meals. Finally, find a healthy pattern and stick to it! Irregular meal frequency causes people to consume more calories than if they follow a regular pattern (11).
See our previous post, To Snack or Not to Snack, for more information on frequency, timing and quality of snacking as it relates to weight management.
- Piernas C. et al. (2010) Snacking increased among U.S. adults between 1977 and 2006. J Nutr. 140:325-332.
- Nielsen SJ, Popkin BM. Changes of beverage intake between 1977 and 2001. Am J Prev Med.2004;27:205–210.
- DiMeglio DP, Mattes RD. Liquid versus solid carbohydrate: effects on food intake and body weight.Int J Obes Relat Metab Disord. 2000;24:794–800.
- Mattes RD and Campbell WW. (2009) Effects of food form and timing of ingestion on appetite and energy intake in lean and obese young adults. J Am Diet Assoc. 109(3):430-437.
- McCrory M et al. (2011) Eating frequency and energy regulation in free-living adults consuming self-selected diets. J. Nutr. 141: 148-153.
- Smeets AJ et al. (2008) Acute effects on metabolism and appetite profile of one meal difference in the lower range of meal frequency. Br J Nutr 99(6):1316-21.
- de Castro JM. (2004) The time of day of food intake influences overall intake in humans. J Nutr. 134(1):104-111.
- Arble DM. (2009) Circadian timing of food intake contributes to weight gain. Obesity (Sliver Spring) 17(11):2100-2102.
- Lucassen EA et al. (2013) Evening chronotype is associated with changes in eating behaviour, more sleep apnea, and increased stress hormones in short sleeping obese individuals. PLoS One 8(3): 356519.
- Geraulet M et al. (2013) Timing of food intake predicts weight loss effectiveness. Int J Obes (Lond) 37(4):604-11.
- Farshchi HR et al. (2004) Decreased thermic effect of food after an irregular compared with a regular meal pattern in healthy lean women. In J Obes Relat Metab Disord 28(5):653-60.