A calorie is not just a calorie. While this is true in a food incinerator, there is more to energy balance than just calories in, calories out when you are talking about the human body. Yes, how many calories you eat matters, but so does what you eat. If you want to develop a lean, athletic body, you need to look for optimal protein levels.
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First, a special note for ladies
While protein is really important for everyone, many ladies tend to shy away from protein. Back in the 80’s when we had that silly low-fat scare, protein often got a bad rep because many protein-containing foods such as meat also contain fat. It seems that despite the available research, this fear continues to linger and many women shy away from protein-rich foods. Many women seem to think that protein will make them big and bulky. As a result, they may still get enough protein to prevent a protein deficiency, but an insufficient amount for optimal results. Ladies, if you want a lean, athletic body, you got to get your protein!
The leanness continuum
As with many things nutrition and training related, context is very important. When addressing the topic of fat loss, you have to consider your level of leanness (i.e. where do you fall on the leanness continuum?). If someone is obese and simply training to move to “less obese” or just overweight, then a simple reduction in calories is sufficient. However, as you move towards higher levels of leanness what you eat becomes a significantly greater factor.
What does the research say?
One of the first low carb ketogenic studies was done by Benoit et al. back in 1965. This study had subjects eat 1000kcal/day with 10g carbs per day (yes, this would totally suck and I’m not recommending it) for 10 days. Average weight loss was 600g/day and of this, 97% of the weight lost was fat.
Famous protein researcher Donald Layman did an excellent study comparing a high protein diet to a high carb diet. In this 10 week study, both groups eat the same amount of calories and about the same amount of fat (around 50g/day). The higher carb group ate 68g of protein per day and lost 6.96kg of fat which is not bad. However, they also lost 3.8g of muscle. The high protein group ate 125g of protein per day and lost 7.53kg of fat and only 1.2g of muscle. Same number of calories, but more protein resulted in more fat loss and less muscle loss. The high protein group also noticed other benefits such as improved blood lipids, glucose homeostasis and satiety (the feeling of fullness – a good thing when you are trying to lose fat).
Samaha et al. also compared high and low carb diets. The high carb group ate 51% of their calories as carbs and ate a total of 1567kcal/day and lost 1.9kg. They also experienced a plateau in weight loss towards the end of the study. The low carb group ate 37% of their daily calories as carbs. Despite the fact that the low carb group actually ate more calories (1630kcal/day instead of 1567kcal/day) they lost 5.8kg and were still losing weight at the 6-month mark. So much for a calorie is a calorie.
Do your own research
No one should ever just cherry-pick a study or two to support their point. You can find studies that do not show much of a difference between higher and lower protein intakes. However, as with any study, you need to consider who the subjects were and how the study was done. As I mentioned at the beginning, when you are going from obese to non-obese, things don’t matter as much. Also, you want to look at what the majority of studies are saying and the majority show that high protein is better than high carb for fat loss. I have included a number of references below if you want to look into this more. You can also do your own Pub Med search in the medical journals HERE. Look at the evidence yourself and always remember to consider how the study was done
How protein can help you get lean
So how does this work? How can the low carb groups (who ate the same or more calories) lose more fat than the high carb group in these research studies? Here are four reasons:
1. Thermic effect of food
Your body requires calories to digest and store the foods you eat. This is known as the thermic effect of food. When you eat fat, about 0-2% of the calories you eat are burned to digest the fat. When you eat carbs, about 5-10% of those calories are burned dealing with the carbs (note: there is a lower thermic effect of food when you eat processed carbs and a higher burn from eating whole, natural carbs). However, when you eat protein, about 20-35% of the calories you consume are burned. As a result if your calorie intake stayed the same, but you simply ate more protein and less carbs and fat, your net calorie burn will be greater. So much for a calorie being a calorie.
2. Retention of lean muscle
Traditional fat loss programs focused on long, slow endurance training and low fat, low protein, high carb diets. This is a great way to lose fat burning muscle. If you are trying to lose body fat, you want to at least maintain if not gain some fat-burning, metabolism-boosting muscle. This can be done by using a program that focuses on strength training and eating an optimal level of protein.
To lose fat you need to be in a caloric deficit. If you reduce fat and protein to reduce total calories, you will feel like you are starving. Protein-rich foods will help you feel more satisfied longer and this helps you consume less total daily calories.
Another possible mechanism is your hormones. By eating less carbs you may reduce insulin levels. This may help because because high levels of insulin promotes fat storage (and increases your risk for type II diabetes. It also increases glucagon levels which can help induce fat burning.
Note: 10 years ago I would have emphasized this point a lot more. However, the reason for the question marks behind hormones is that it doesn't seem to be as big of a deal as we once thought. Maybe it helps, maybe not. However, regardless of the how we know the what - eat more protein.
So how much protein should you eat?
This can vary depending on how much you are training. As a general guideline, I suggest about 0.6-1g of protein per pound of body weight. Great options for protein-rich foods include: chicken, turkey, buffalo, beef, wild game, fish and if tolerated well, cottage cheese and milk-based protein powders (note: thermic effect of food will be lower in protein powders).
Related: Finding Your Optimal Protein Level.
You still need carbs
Oh how the diet industry loves to take things to the extreme! While getting more protein is important, you want to avoid the common mistake of thinking protein = good, carbs = bad. If you are doing hard, athletic training, you need your carbs. The trick is finding the right amount for you. Eat enough that you can effectively fuel high-intensity training, but not so much that it prevents you from getting to and staying at your ideal body composition.
Related: How to Personalize Your Carb Intake
One final note:
I know this may be obvious, but just for total clarity: if you simply just add more protein to your current diet without subtracting some carbs or fat, you will not lose fat.
References and additional resources:
Note: many of the additional references deal with low carb vs. high carb, not just protein
- Antonio, J, et. al (eds.). Essentials of Sports Nutrition and Supplements. Totowa, NJ: Humana Press; 2008.
- Benoit FL, Martin RL, Watten RH. Changes in body composition during weight reduction in obesity. Balance studies comparing effects of fasting and a ketogenic diet. Annals of Internal Medicine. 1965; 63(4): 604-612.
- Brehm BJ, Seeley RJ, Daniels SR, D'Alessio DA. A randomized trial comparing a very low carbohydrate diet and a calorie-restricted low fat diet on body weight and cardiovascular risk factors in healthy women. Journal of Clinical Endocrinology & Metabolism. 2003 Apr;88(4):1617-23.
- Ebbeling CB, Leidig MM, Feldman HA, Lovesky MM, Ludwig DS. Effects of a low-glycemic load vs low-fat diet in obese young adults: a randomized trial. Journal of the American Medical Association. 2007 May 16;297(19):2092-102. Erratum in: JAMA. 2007 Aug 8;298(6):627.
- Gardner CD, Kiazand A, Alhassan S, Kim S, Stafford RS, Balise RR, Kraemer HC, King AC. Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A TO Z Weight Loss Study: a randomized trial. Journal of the American Medicine Association. 2007 Mar 7;297(9):969-77. Erratum in: JAMA. 2007 Jul 11;298(2):178.
- Hession M, Rolland C, Kulkarni U, Wise A, Broom J. Systematic review of randomized controlled trials of low-carbohydrate vs. low-fat/low-calorie diets in the management of obesity and its comorbidities. Obesity Reviews. 2009 Jan;10(1):36-50. Epub 2008 Aug 11. Review.
- Klemsdal TO, Holme I, Nerland H, Pedersen TR, Tonstad S. Effects of a low glycemic load diet versus a low-fat diet in subjects with and without the metabolic syndrome. Nutrition, Metabolism & Cardiovascular Diseases. 2009 Jun 5. [Epub ahead of print]
- Lasker DA, Evans EM, Layman DK. Moderate carbohydrate, moderate protein weight loss diet reduces cardiovascular disease risk compared to high carbohydrate, low protein diet in obese adults: A randomized clinical trial. Nutrition & Metabolism. (Lond). 2008 Nov 7;5:30.
- Layman DK, Boileau RA, Erickson DJ, et al. A reduced ratio of dietary carbohydrate to protein improves body composition and blood lipid profiles during weight loss in adult women. Journal of Nutrition. 2003: 133(2): 411-417.
- Maki KC, Rains TM, Kaden VN, Raneri KR, Davidson MH. Effects of a reduced-glycemic-load diet on body weight, body composition, and cardiovascular disease risk markers in overweight and obese adults. American Journal of Clinical Nutrition. 2007 Mar;85(3):724-34.
- McMillan-Price J, Petocz P, Atkinson F, O'neill K, Samman S, Steinbeck K, Caterson I, Brand-Miller J. Comparison of 4 diets of varying glycemic load on weight loss and cardiovascular risk reduction in overweight and obese young adults: a randomized controlled trial. Archives of Internal Medicine. 2006 Jul 24;166(14):1466-75.
- Meckling KA, Sherfey R. A randomized trial of a hypocaloric high-protein diet, with and without exercise, on weight loss, fitness, and markers of the Metabolic Syndrome in overweight and obese women. Applied Physiology, Nutrition, and Metabolism. 2007 Aug;32(4):743-52.
- Moses RG, Barker M, Winter M, Petocz P, Brand-Miller JC. Can a low-glycemic index diet reduce the need for insulin in gestational diabetes mellitus? A randomized trial. Diabetes Care. 2009 Jun;32(6):996-1000. Epub 2009 Mar 11.
- Pereira MA, Swain J, Goldfine AB, Rifai N, Ludwig DS. Effects of a low-glycemic load diet on resting energy expenditure and heart disease risk factors during weight loss. Journal of the American Medical Association. 2004 Nov 24;292(20):2482-90.
- Philippou E, Bovill-Taylor C, Rajkumar C, Vampa ML, Ntatsaki E, Brynes AE, Hickson M, Frost GS. The effect of a 6-month dietary glycemic index manipulation in addition to healthy eating advice and weight loss on arterial compliance and 24-hour ambulatory blood pressure in men: a pilot study. Metabolism. 2009 Jul 13. [Epub ahead of print]
- Retterstøl K, Hennig CB, Iversen PO. Improved plasma lipids and body weight in overweight/obese patients with type III hyperlipoproteinemia after 4 weeks on a low glycemic diet. Clinical Nutrition. 2009 Apr;28(2):213-5. Epub 2009 Feb 20.
- Samaha FF, Iqbal N, Seshadri P, et al. A low-carbohydrate as compared with a low-fat diet in severe obesity. New England Journal of Medicine. 22 2003; 348(21): 2074-2081.
- Shai I, Schwarzfuchs D, Henkin Y, Shahar DR, Witkow S, Greenberg I, Golan R, Fraser D, Bolotin A, Vardi H, Tangi-Rozental O, Zuk-Ramot R, Sarusi B, Brickner D, Schwartz Z, Sheiner E, Marko R, Katorza E, Thiery J, Fiedler GM, Blüher M, Stumvoll M, Stampfer MJ; Dietary Intervention Randomized Controlled Trial (DIRECT) Group. Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet. New England Journal of Medicine. 2008 Jul 17;359(3):229-41.
- Smith-Ryan, AE. & Antonio, J. (eds.). Sports Nutrition & Performance Enhancing Supplements. New York: Linus Publications; 2013.
- Tay J, Brinkworth GD, Noakes M, Keogh J, Clifton PM. Metabolic effects of weight loss on a very-low-carbohydrate diet compared with an isocaloric high-carbohydrate diet in abdominally obese subjects. Journal of the American College of Cardiology. 2008 Jan 1;51(1):59-67.
- Thomas DE, Elliott EJ, Baur L. Low glycaemic index or low glycaemic load diets for overweight and obesity. Cochrane Database Systematic Review. 2007 Jul 18;(3):CD005105. Review.
- Volek J, Sharman M, Gómez A, Judelson D, Rubin M, Watson G, Sokmen B, Silvestre R, French D, Kraemer W. Comparison of energy-restricted very low-carbohydrate and low-fat diets on weight loss and body composition in overweight men and women. Nutrition & Metabolism. (Lond). 2004 Nov 8;1(1):13.
- Wood RJ, Fernandez ML. Carbohydrate-restricted versus low-glycemic-index diets for the treatment of insulin resistance and metabolic syndrome. Nutrition Reviews.. 2009 Mar;67(3):179-83. Review.
- Yancy WS Jr, Olsen MK, Guyton JR, Bakst RP, Westman EC. A low-carbohydrate, ketogenic diet versus a low-fat diet to treat obesity and hyperlipidemia: a randomized, controlled trial. Annals of Internal Medicine. 2004 May 18;140(10):769-77.