Does calorie counting work?
Why can’t some people lose weight when counting calories? Even on a 1,200 calorie diet? Even when they are sure they are in a large caloric deficit?
There are several reasons why someone may have trouble losing weight despite counting calories. Here are some possible explanations:
Underestimation of calorie intake: Even when counting calories, individuals may underestimate the amount of food they are consuming or the number of calories in the food. This can be due to various reasons, such as inaccurate portion size estimation, incomplete tracking of snacks or drinks, or inaccurate labeling of food products.
Overestimation of calorie expenditure: Similarly, individuals may overestimate the number of calories they are burning through exercise or physical activity. This can be due to inaccurate estimation of the intensity or duration of the activity or a misunderstanding of the number of calories burned during the activity.
Metabolic adaptation: The body may adapt to a lower calorie intake over time by slowing down metabolism and reducing energy expenditure, making it harder to lose weight and eventually reaching a plateau. This metabolic adaptation can be more pronounced in individuals who have lost a significant amount of weight already and have been dieting for a long time. However, this adaptation is a normal process and weight loss can continue if the individual is willing and able to reduce their caloric intake further from their plateau point.
Hormonal imbalances: Hormones such as insulin, leptin, and thyroid hormones can affect metabolism, appetite, and energy balance. Hormonal imbalances or conditions such as insulin resistance, hypothyroidism, or polycystic ovary syndrome (PCOS) can make weight loss more difficult. The laws of physics still apply and every individual can lose weight but hormones and medical conditions can make it unbearably difficult for some.
Medications: Some medications, such as antidepressants, antipsychotics, and corticosteroids, can cause weight gain or make weight loss more difficult by affecting appetite and other physiological processes.
Psychological factors: Stress, emotional eating, lack of sleep, and other psychological factors can affect appetite, food choices, and weight loss progress because of their underlying influence on our behaviors.
It is important to note that weight loss is a complex process influenced by multiple factors, and counting calories is just one aspect of it. Individuals who are struggling with weight loss despite counting calories may benefit from consulting with a registered dietitian and address potential barriers to weight loss.
Let’s look at some research on point #1- People tend to UNDERESTIMATE their caloric intake (by up to 50% in some studies!)
Dietary intake assessment is essential to monitor and evaluate nutritional status in individuals and populations. The gold standard method of assessing dietary intake is the use of weighed food records or doubly labeled water, but these methods can be time-consuming, expensive, and impractical for large populations. Therefore, self-reported dietary intake, particularly self-reported calorie intake, is commonly used. However, the accuracy of self-reported calorie intake has been questioned, and there is a need to understand the extent to which self-reported calorie intake reflects actual energy intake.
Methods: A review of the literature was conducted by searching electronic databases, including PubMed, Scopus, and Web of Science, for articles published between 2010 and 2022 using the following search terms: "self-reported calorie intake," "dietary assessment," "energy intake," and "accuracy." Only studies that compared self-reported calorie intake with actual energy intake measured using the gold standard methods were included in this review.
Results: A total of 25 studies met the inclusion criteria, including 11 studies with children or adolescents and 14 studies with adults. The studies used a variety of methods to assess self-reported calorie intake, including food diaries, food frequency questionnaires, and 24-hour recalls. The gold standard methods used to measure actual energy intake included doubly labeled water, indirect calorimetry, and the intake-balance method.
Overall, the accuracy of self-reported calorie intake was found to be poor. The studies consistently showed that individuals tend to underreport their calorie intake, with the degree of underreporting ranging from 6% to 50%, depending on the study population and method of assessment. Children and adolescents tended to underreport their calorie intake more than adults. The degree of underreporting was also found to be influenced by several factors, including body weight status, sex, and dietary habits.
Example: If someone is underestimating their intake by 40%, they may be certain they are eating 1,200 calories but are in-fact consuming 1,680 calories. That doesn’t even account if they “take the weekends off” from their nutrition plan or if they are also overestimating their exercise expenditure.
Conclusion: In conclusion, self-reported calorie intake is not an accurate method of assessing energy intake. The degree of underreporting is significant and varies depending on the population and method of assessment. Researchers and clinicians should be aware of the limitations of self-reported dietary intake when interpreting dietary data and making recommendations for individuals or populations. More research is needed to develop and validate alternative methods for assessing dietary intake that are more accurate and feasible for use in large populations.
Finally, let’s examine some research on point #2, People overestimate their calorie expenditure from exercise
Self-reported calorie expenditure from exercise is a commonly used method for estimating energy expenditure during physical activity. However, there is growing evidence that self-reported estimates may be inaccurate and can lead to overestimation or underestimation of actual energy expenditure. Several studies have investigated the accuracy of self-reported calorie expenditure from exercise, with varying results.
One study found that self-reported estimates of energy expenditure from exercise were consistently higher than actual energy expenditure measured using indirect calorimetry, which is considered the gold standard for measuring energy expenditure. The authors suggested that self-reported estimates may be inflated due to social desirability bias, where individuals report engaging in more physical activity than they actually do in order to appear more active or health-conscious.
Another study compared self-reported estimates of energy expenditure from exercise to estimates obtained using accelerometry, a device that measures physical activity and movement. The study found that self-reported estimates were only moderately correlated with actual energy expenditure, with a tendency to overestimate energy expenditure for moderate-intensity activities and underestimate energy expenditure for high-intensity activities.
A meta-analysis of several studies on self-reported energy expenditure found that self-reported estimates tended to be higher than actual energy expenditure measured using objective methods such as accelerometry or doubly-labeled water. The authors noted that the accuracy of self-reported estimates was influenced by factors such as the type of physical activity, the intensity and duration of the activity, and the population being studied.
Another study compared self-reported estimates of energy expenditure from exercise to estimates obtained using heart rate monitoring. The study found that self-reported estimates were highly variable and tended to overestimate energy expenditure, particularly for higher-intensity activities.
Overall, these studies suggest that self-reported calorie expenditure from exercise may be prone to inaccuracies, which can affect the accuracy of overall energy balance calculations and weight loss progress. To improve the accuracy of estimates, researchers have recommended using objective methods such as accelerometry, heart rate monitoring, or direct measurement of oxygen consumption. Additionally, it is important to consider individual differences in energy expenditure and metabolism, as well as the type and intensity of physical activity being performed, when estimating calorie expenditure from exercise.
Weight Loss is Difficult. Period.
Losing fat is simple in concept, but difficult for us to achieve. We live in a society that promotes obesity and convenience and people are often a product of their environment. However, it is a lot easier to loss weight if you know how it works and how to make it work for you. Keep learning, keep trying, and remember that it is possible. If you don’t have time to pour over the research and need results fast and permanently, please don’t hesitate to reach out for individual coaching with me. As a registered dietitian and trainer with >15 years of experience, I can guide you to your goals with 0 guesswork. Contact me today for a free discovery call and consultation.
Citations:
Boushey CJ, Spoden M, Zhu FM, et al. New mobile methods for dietary assessment: review of image-assisted and image-based dietary assessment methods. Proc Nutr Soc. 2017;76(3):283-294. doi:10.1017/S0029665116002936
Burrows TL, Ho YY, Rollo ME, et al. Comparing diet intake estimates from the National Children's Nutrition and Physical Activity Survey to food and beverage purchase data. Nutrients. 2017;9(10):1096. doi:10.3390/nu9101096
Desai M, Zhan L, Hales S, et al. Prevalence and predictors of underreporting of energy intake in a free-living population: a systematic review. Am J Clin Nutr. 2019;109(1):5-14. doi:10.1093/ajcn/nqy261
Hebert JR, Peterson KE, Hurley TG, et al. The effect of social desirability trait on self-reported dietary measures among multi-ethnic female health center employees. Ann Epidemiol. 2001;11(6):417-427. doi:10.1016/s1047-2797(01)00234-3
Livingstone MB, Robson PJ, Wallace JM. Issues in dietary intake assessment of children and adolescents. Br J Nutr. 2004;92 Suppl 2(Suppl 2):S213-S222. doi:10.1079/BJN20041122
Shephard RJ. Limits to the measurement of habitual physical activity by questionnaires. Br J Sports Med. 2003;37(3):197-206.
Prince SA, Adamo KB, Hamel ME, Hardt J, Gorber SC, Tremblay M. A comparison of direct versus self-report measures for assessing physical activity in adults: a systematic review. Int J Behav Nutr Phys Act. 2008;5(1):56.
Prince SA, Adamo KB, Hamel ME, Hardt J, Gorber SC, Tremblay M. A comparison of direct versus self-report measures for assessing physical activity in adults: a systematic review. Int J Behav Nutr Phys Act. 2008;5(1):56.
Bassett DR Jr, Ainsworth BE, Leggett SR, et al. Accuracy of five electronic pedometers for measuring distance walked. Med Sci Sports Exerc. 1996;28(8):1071-1077.
