Portion size is often touted as the key to weight control. Nutrient dense foods, high in nutrients and low in calories, are helpful in this regard. Another popular recommendation is for people to snack between meals. Snacking is proposed to foster weight control for several reasons:
- Snacking may help maintain blood glucose levels, keeping cravings under control.
- Snacking may optimize metabolism and calorie-burning.
- Snacking may improve satiety and help you avoid overeating at meals.
But does snacking *really* help achieve these goals? Are there circumstances where it could hinder weight loss or maintenance efforts?
Recent studies have called into question whether snacking is an effective strategy and suggest that snacking could actually precipitate weight gain and contribute to the growing obesity epidemic. How strong is the science supporting snacking? Have the benefits of snacking been oversold? Have we lost sight of what “smart” snacking actually is?
In a review on the effect of snacking on energy balance, Chapelot  argues that research does not support a satiety-improving effect of snacking. Often there is no meal-time compensation for earlier snacking; thus, leading to overall positive energy balance and weight gain. Even within the literature, however, our definition of “snacking” may be to blame for the confusion surrounding the influence of between-meal eating on weight loss and maintenance . Snacking frequency, composition and timing are all important factors that may help distinguish smart snacking from unnecessary eating.
FREQUENCY. Adults are eating more frequently during the day and the number of calories consumed in between-meal snacks has grown dramatically . Greater eating frequency is often associated, both anecdotally and in research studies, with weight loss success and lower body weight. A recent cross-sectional study by Bachman et al.  found that normal weight (mean BMI = 21.1) and weight-loss maintainers (mean BMI = 22.1) snacked more often than obese individuals (mean BMI = 32.4) – typically 3 meals and 2 snacks per day. Interestingly, greater snacking frequency was also associated with higher energy intake but balanced out with greater physical activity.
Findings are different, however, in weight loss interventions. A randomized controlled study looked at the effect of snacking in individuals with obesity. The participants were assigned to one of two groups: 3 meals/day or 3 meals + 3 snacks/day . They report that both groups decreased their energy intake and lost weight. However, after one year, there was no difference in daily caloric intake, weight loss or metabolic indices (such as blood lipids, etc.) between the two groups. Interestingly, only 50% of participants in each group found their assigned eating pattern “easy” to follow, though there was a non-significant increase in the 3+3 group’s willingness to continue with their plan . These results suggest that a hypocaloric diet, regardless of the inclusion of a snack, promotes weight loss but personal preference is likely to play a role in success.
TIMING. Kong et al.  recently reported that snack timing could alter weight loss results: in postmenopausal women (mean BMI = 31.3), mid-morning snackers lost an average of 7% of their total body weight while those who ate a healthy breakfast but did not snack before lunch lost more than 11% of their body weight. Interestingly, mid-morning snackers were more likely to snack at another time point in the day, though total number of snacks per day (1 to 3+) was not associated with the degree of weight loss.
Although not statistically significant, there were trends towards greater weight loss with an afternoon snack and less weight loss with a late-evening snack, defined at 9 pm – 12 am . Other studies have demonstrated snacking later in the evening, particularly after 11 pm (i.e., nocturnal eating) is associated with increased caloric intake and weight gain . The likelihood of mindless and distracted eating, such as tv viewing, in the evening is higher than at other time points; therefore, nighttime snacking may occur in the absence of actual hunger.
QUALITY. Kong et al.  found that snacking was an important source of vegetables, fruit and fibre, but did not elaborate on composition or quality of snacks with respect to weight loss success. To maximize fullness, snacks should be whole foods instead of calorie-containing beverages. Calorie-laden fluids do not stimulate the same satiety as semi-solid or solid foods and can lead to overeating and weight gain . The protein content may also be important. Findings suggest that whole food snacks with a high-protein content increased satiety (hypothetically reducing appetite and intake at the subsequent meal), more so than carbohydrate-based or high-fat snacks .
No Baloney’s Advice? As Leidy and Campbell  point out, eating frequency and weight loss is a delicate balance: eating too often can increase caloric intake and sabotage weight loss, while skipping meals has negative impact on appetite control. Weight loss recommendations should be personalized. A blanket recommendation for between-meal snacks can be detrimental – it’s still about the basics of calorie balance and portion control.
- Listen to what your body is telling you. Include snacks if you are ravenous by the next meal. Rate hunger on a 10-point scale – if you are an 8, 9 or 10 at lunch/dinner… you would benefit from a between-meal snack. If there is a short period of time between meals (like breakfast to lunch) and you are still ravenous, you may just need a better breakfast, try steelcut oats + berries + walnuts.
- Focus on nutrient-dense but still lower calorie choices – these are snacks, not meals. Thinks fruits or veggies with a bit of protein (i.e., yogurt, humus, nuts, etc.) – this combination of protein and fibre will help you feel full longer.
- If you are not sure whether you need a snack, drink a big glass of water first. Hunger can be amplified by thirst. Choose no-calorie (but not artificially sweetened) beverages most often: water, herbal tea, etc.
- Control mealtime eating: it’s about portion control. Resist the urge to hoover your food and eat slowly. Stop when you are full – there is no place for feast-or-famine eating given today’s issues with obesity. Make a concerted effort to put down the fork before you are full, let your food settle, and then reassess hunger.
- Keep the mindless eating in check: avoid eating at your desk while you work and in front of the tv.
Research suggests that snacking between-meals can be an important source of veggies, fruit, fibre and accompanying micronutrients, however, the jury is still out with respect to the utility of snacking for weight loss and maintenance. More research is needed to determine whether frequency, timing and quality of snacks plays a role in weight loss and for whom snacking is most appropriate.
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2. Gregori D, Foltran F, Ghidina M, Berchialla P. Understanding the influence of the snack definition on the association between snacking and obesity: a review. Int J Food Sci Nutr 2011; 62: 270-5.
3. Popkin BM, Duffey KJ. Does hunger and satiety drive eating anymore? Increasing eating occasions and decreasing time between eating occasions in the United States. Am J Clin Nutr 2010; 91:1342-7.
4. Bachman JL, Phelan S, Wing RR, Raynor HA. Eating frequency is higher in weight loss maintainers and normal-weight individuals than in overweight individuals. J Amer Diet Assoc 2011; 111:1730-4.
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