19 Reasons Why Calorie Counting Doesn’t Work

April 19th, 2019 | Posted in Info

It may be true that eating a lot more calories than you can burn off will most likely lead to weight gain and eating a lot fewer than you burn off will lead to weight loss. However, there are many other variables to consider. Here are a few problems with the calorie counting method of weight control:

1. The calorie content of food is hard to measure. The values given on food labels are often wildly inaccurate. American government regulations allow labels to understate calories by up to 20%.

2. Every body digests differently. Some people will digest and absorb more calories from the same food than others depending on the efficiency of their digestive system.

3. The length of the intestines varies hugely. Those with shorter intestines absorb fewer calories before the food is eliminated.

4. We all have a unique microbiome which plays a big role in digestion, absorption and weight.

5. The time of day that food is eaten may affect what the body does with the calories.

6. Our genes affect how we use and store calories. Certain genes are more likely to be found in overweight people compared to slim people.

7. Quality and length of sleep affect energy usage and storage. Lack of sleep may cause the body to lay down more fat.

8. Different people have a different insulin response to food. This affects whether calories are stored as fat.

9. Previous dieting will affect what your body does with food. The body often wants to regain the weight that is lost, slowing metabolism and reducing energy expenditure.

10. Eating schedules can affect body weight and fat storage. For example, intermittent fasting in which a longer period is left between the evening meal and breakfast, is helpful for some people.

11. Reducing fat intake may well reduce calorie intake but will also reduce the intake of essential fatty acids and fat soluble vitamins which are vital for many aspects of body function and metabolism.

12. Artificial sweeteners may have zero calories but research shows that they lead to weight gain through various mechanisms including changes in gut bacteria. disrupting appetite signals, increased food consumption and reduced metabolism after meals (1,2,3).

13. In the short term reducing calorie intake may be counteracted by mechanisms in the body that reduce metabolic rate and increase calorie intake, ensuring the regaining of lost weight (4). For example, even a year after dieting, hormonal mechanisms that stimulate appetite are raised (5).

14. The use of calorie tracking apps and activity monitors is on the rise but research suggests that these trackers may trigger, maintain, or exacerbate eating disorders (6).

The Effects of Food Preparation on Calorie Absorption

15. How food is prepared affects how much is absorbed and how much eliminated. Blending food does part of the work of digestion, making more calories available to your body.

16. Heating food increases the proportion of food digested in the stomach and small intestine. The digestible calories in sweet potato increase by about 40% when cooked although this varies depending on the cooking method.

17. The calorie absorption of carbohydrate heavy foods such as rice, pasta and potatoes can be reduced by cooking then chilling them. During the cooling process some of the carbs become resistant starch which is indigestible.

18. Adding oil, lemon juice or cider vinegar to cooked carbs such as rice can reduce the calorie absorption and insulin response.

19. Different parts of plant foods may be digested and absorbed differently. For example, the interior of sweetcorn kernels is easily digested but the cellulose husk is impossible to break down and passes through the body untouched.

For more information see also the blog posts on Not All Calories are Equal and The History of the Calorie.



1. Physiol Behav. 2016 Apr 26. pii: S0031-9384(16)30184-6. Low-calorie sweetener use and energy balance: Results from experimental studies in animals, and large-scale prospective studies in humans. Fowler SP

2. Trends Endorcrinol Metab. 2013 Sep;24(9):431-41. Artificial sweeteners produce the counterintuitive effect of inducing metabolic derangements. Swithers SE

3. PLOS Medicine, January 2017 Artificially Sweetened Beverages and the Response to the Global Obesity Crisis. Borges M, Louzada M, de Sa TH, Laverty AA, et al.

4. Calonne J, Isacco L et al.Reduced Skeletal Muscle Protein Turnover and Thyroid Hormone Metabolism in Adaptive Thermogenesis That Facilitates Body Fat Recovery During Weight Regain. Front Endocrin (Lausanne) 2019 Feb 28;10:119

5. Benton D, Young HA. Reducing Calorie Intake May Not Help You Lose Body Weight. Perspect Psychol Sci. 2017 Sep;12(5):703-714

6. Simpson CC, Mazzeo SE. Calorie counting and fitness tracking technology: Associations with eating disorder symptomatology. Eat Behav. 2017 Aug;26:89-92