Q: I’ve heard that eating more frequently will increase my metabolism and help me lose weight? Is this true and how does this happen? I thought you had to eat less to lose weight.
A: You’ve probably heard this advice from many different places: personal trainers at your gym, online weight-loss websites, and popular diet books. Even though it has some merit, it may not be entirely correct, especially if your physical activity levels are low or non-existent.
The suggestion to increase your eating frequency, meaning going from eating three square meals a day to six smaller meals and snacks, stems from both research and anecdotal findings. Some of the benefits attributed to eating more often include reducing hunger and caloric intake, boosting your metabolic rate, and controlling hormones that increase your desire for food. For some people this is true, for others, not so much.
In the research world, scientists have shown certain benefits from eating more often compared to less:
• By eating the same amount of calories in several meals spread throughout the day there’s a suppression of free fatty acid release from adipose tissue, which enhances your ability to use glucose (from carbohydrate foods) as fuel
• The amount of insulin secreted from your pancreas to help you use the nutrients you’re eating is reduced, so there is less potential for those nutrients to be stored in fat cells. Instead, the insulin that is released sends those calories to your needy muscle cells where they’re used to provide energy for daily movement
• Your stomach is stretched less with smaller meals, which slows the rate at which food is delivered to your intestine, and in turn, your blood stream. This creates a consistent flow of energy to your body rather than one fast, large dump of nutrients
• Blood total and LDL-cholesterol levels in your body are decreased due to less cholesterol synthesis and increased cholesterol removal
Despite these findings, reviews of all the scientific investigations looking at the effect of increased eating on weight loss have not shown that eating more often reduces body weight. The recent review by Palmer and colleagues in 2009, and the ones by Bellisle and colleagues in 1997 both found this same result; eating more often does not seem to decrease body weight in every person. Explanations for this finding includes the fact that the energy density of our food has increased over the years, even though we’re evolutionarily meant to be “grazers”. Even with lower calories, eating more frequently does not help decrease the numbers on the scale by itself.
For body composition, some observations of people that eat more rather than less show that their body carries less fat. However, research investigations have not shown that just going from eating less to eating more magically lowers body fat. Those people that eat more may simply burn more calories naturally during the day, or expend more calories in movement. Then there are those people that never gain fat no matter how hard they try (not the norm nowadays though).
However, there are clear benefits to eating more often:
• You stave off hunger before it sets in and pushes you to overeat
• You give yourself more energy to exercise harder
• You prevent swings in your blood sugar levels which can make you cranky, unhappy and lethargic
As far as increasing your metabolism, eating more often can potentially increase the amount of calories you burn in a day, by a mechanism known as the “Thermic Effect of Feeding”. However, this effect is relatively small and can be made easily obsolete with poor food choices and excess caloric intake.
It is true though that when you eat more often rather than less, you’re more likely to meet your exercise goals instead of not having the energy to even begin to do anything. Then, when you exercise more, especially a combination of weight training and cardio, you can increase your muscle mass and lower your body fat, which makes your body look tighter and fit better in clothing. And who doesn’t want that?
However, eating more often doesn’t work for everyone: If you’re not exercising, eating more will definitely cause fat gain – those calories have no where else to go! And, when you eat more you still have to make good food choices and balance your intake of protein, carbohydrates and fat; eating more chocolate and soda will not help your metabolism at all. Considering that most “snack” foods are based off sugar and starchy carbohydrates (crackers, granola bars, etc), it’s really easy to over-consume carbs and miss out on important proteins and fats.
Bottom line: Eating more can help meet your body composition and weight goals if you’re selecting your nutrients wisely and using them to help you exercise consistently.
Palmer MA, Capra S, & Baines SK. Association between eating frequency, weight, and health. Review
Nutr Rev. 2009 Jul;67(7):379-90
Bellisle F, McDevitt R, Prentice A. Meal frequency and energy balance. Brit J Nutrition. 1997;77(Suppl 1):S57–S70
Jenkins D, Wolever T, Vuksan V, et al. Nibbling versus gorging: metabolic advantages of increased meal frequency. N Engl J Med. 1989;321:929–934
Frequent Eating Associated with Lower Lipid Concentrations. JWatch General. 2002: 3-3
Farshchi HR, Taylor MA, Macdonald IA. Beneficial metabolic effects of regular meal frequency on dietary thermogenesis, insulin sensitivity, and fasting lipid profiles in healthy obese women. American Journal of Clinical Nutrition. 2005;81:16-24
Ruidavets JB, Bongard V, Bataille V, et al. Eating frequency and body fatness in middle-aged men International Journal of Obesity. 2002; 26: 1476-1483