Weight loss boils down to calories in vs calories out.
You’ve heard this axiom countless times, and there is much truth in it.
But, the reality is that not all calories are the same.
How can this be?
Let’s discuss what a calorie really is.
What Is a Calorie?
When we hear the word “calorie,” we most often think of it in terms of how much energy a particular food or meal contains.
While that is one meaning of the word calorie, its origins date back to the 1800s where it was defined as the amount of energy required to raise the temperature of one gram of water by one degree Celsius.
To find out how much energy a particular food contains, scientists would place a food (such as an apple) in a sealed stainless steel container called a “bomb” and then place it in a copper chamber which is filled with water. Heat is applied to said food until it burns, which generates a considerable amount of heat and slowly heats the surrounding water.
Scientists then measure how high the water temperature rises and then calculate the number of calories the food contains.
While bomb calorimetry is accurate, it is a slow and tedious process.
These days, calorie contents of foods are calculated by adding up the individual macronutrients of the food.
Each macronutrient has the following caloric values:
- 1 gram of protein = 4 calories
- 1 gram of carbohydrates = 4 calories
- 1 gram of alcohol = 7 calories
- 1 gram of fat = 9 calories
However, if you add up the macronutrients on a given food in your pantry or freezer, you’ll likely see that there is a slight discrepancy. This is due to the fact that the FDA allows for a small margin of error and rounding (“wiggle room”) on the nutrition facts panel. For instance, if a product contains less than 0.5 grams of fat, it can be labeled as “fat-free” and have 0g fat listed on the nutrition facts panel.[1]
But, there’s more…
Not All Calories Are Equal
Our bodies metabolize each macronutrient slightly differently.
Certain foods force your body to use more energy (calories) for digestion than other foods. Plus, certain foods can also help you to feel less hungry after eating them.
Protein, for instance, is the most thermogenic macronutrient, meaning that your body spends more energy to digest protein-rich foods than it does carbohydrates or fat. Armed with this knowledge, you can structure your diet to make it easier to stick to your calorie goals for the day and get the weight loss or transformation challenge results you’re after!
How Diet Impacts Energy Expenditure (TDEE)
The total number of calories you burn each day is called total daily energy expenditure (TDEE).
It is comprised of four parts:
- Resting metabolic rate (RMR): The amount of calories your body burns at rest performing life-sustaining functions.
- Thermic Effect of Activity (TEA): the number of calories you burn during structured physical activity (a.k.a. exercise).
- Non-Exercise Activity Thermogenesis (NEAT): the number of calories burned each day from movement not classified as structured exercise. Activities such as walking from one room to another, taking the stairs, blinking, tapping your foot, and fidgeting all count towards your daily NEAT.
- Thermic Effect of Feeding (TEF): the number of calories your body expends breaking down the carbohydrates, protein, and fat you eat into sugars, amino acids, and fatty acids
Physical activity and nutrition are highly variable from one individual to another and within the same individual from one day to the next. What this means is that the choices you make on a daily basis can have a significant impact on the amount of energy you burn and the amount of energy you consume each day.
Keep in mind that the largest contributor to TDEE is your resting metabolic rate, which accounts for 65-80% of the calories you burn every day.
Why Higher Protein Diets Are Better for Weight Loss
As we mentioned, protein is the most thermogenic macronutrient, forcing your body to expend more calories to digest compared to carbohydrates or fat.
Plus, protein is also the most satiating macronutrient, which can help you to stay full for longer after eating, and thereby less likely to snack in-between meals.
This is why research shows that high-protein diets lead to better weight loss/maintenance compared to lower protein diets.[2,3,4]
Something else to consider is that protein helps your body to recover from intense workouts and build lean muscle mass -- the more lean muscle you have, the more calories your body burns at rest.
But, protein isn’t the only thing that can help you to keep your calorie intake in check.
Fiber Helps, Too!
Fiber is the indigestible carbohydrate portion of plant foods. While our muscles can’t use it for workouts or replenishing glycogen, it does serve several important roles in the body, including feeding the healthy bacteria in our gut.
Fiber also helps to help you feel more satiated after eating, and adequate fiber intake has been recognized by researchers as an important component in weight loss as well as supporting cardiometabolic health.[5,6]
Plant foods (fruits, vegetables, whole grains, legumes, nuts, and seeds) are great sources of natural fiber. If you have difficulty getting enough fiber from your diet, you can use a fiber supplement, such as 1UP Fiber Plus -- every serving delivers 7 grams of natural fiber from psyllium husk, inulin, and golden flaxseed.
Takeaway
While calories in vs calories out does ultimately dictate weight loss/weight gain. Choosing certain foods can help you to feel fuller and less hungry after eating, which can help you to consume fewer calories during the day, and get the weight loss results you want!
References
- https://www.fda.gov/files/food/published/Food-Labeling-Guide-%28PDF%29.pdf
- Moon J, Koh G. Clinical Evidence and Mechanisms of High-Protein Diet-Induced Weight Loss. J Obes Metab Syndr. 2020 Sep 30;29(3):166-173. doi: 10.7570/jomes20028. PMID: 32699189; PMCID: PMC7539343.
- Kim JY. Optimal Diet Strategies for Weight Loss and Weight Loss Maintenance. J Obes Metab Syndr. 2021 Mar 30;30(1):20-31. doi: 10.7570/jomes20065. PMID: 33107442; PMCID: PMC8017325.
- Leidy HJ, Clifton PM, Astrup A, Wycherley TP, Westerterp-Plantenga MS, Luscombe-Marsh ND, Woods SC, Mattes RD. The role of protein in weight loss and maintenance. Am J Clin Nutr. 2015 Jun;101(6):1320S-1329S. doi: 10.3945/ajcn.114.084038. Epub 2015 Apr 29. PMID: 25926512.
- Miketinas DC, Bray GA, Beyl RA, Ryan DH, Sacks FM, Champagne CM. Fiber Intake Predicts Weight Loss and Dietary Adherence in Adults Consuming Calorie-Restricted Diets: The POUNDS Lost (Preventing Overweight Using Novel Dietary Strategies) Study. J Nutr. 2019 Oct 1;149(10):1742-1748. doi: 10.1093/jn/nxz117. PMID: 31174214; PMCID: PMC6768815.
- Slavin JL. Dietary fiber and body weight. Nutrition. 2005 Mar;21(3):411-8. doi: 10.1016/j.nut.2004.08.018. PMID: 15797686.
