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How Does Protein Intake Affect Weight Loss?

girl on a mission protein and weight loss

How Protein Influences Weight Loss

There are 3 main ways that protein intake can positively affect weight loss

 

1) Protein consumption promotes feeling of fullness (Satiety)

(Leidy, Carnell, Mattes, Campbell, 2007; Weigle et al., 2005; Einstein et al, 2002)

  • Satiety – since hunger is one of main reasons why dieters fail to stay on weight loss diet (Johnstone, 2009)
  • Studies of weight loss using higher protein diets consistently report increased satiety

 

2) Protein consumption requires an increased amount of energy (calories) to digest
  • Thermogenesis
  • 10 – 24% of total energy expended in any given day (Einstein et al, 2002)
  • Review of studies looking at this “thermal effect” of food [mixed meals & isolated macronutrient studies] find that protein contributes twice as much to TEF
  • Small but significant –>  2 – 3 lb loss advantage for 30% over 15% intake in a year (Einstein et al, 2002)

 

3) Protein consumption promotes preservation of lean body tissue (preserves muscle)

(Leidy, Carnell, Mattes, & Campbell, 2007; Halton & Hu, 2004)

  • Weight loss commonly results in loss of both fat & muscle (body proteins)
  • Even though desire is fat loss
  • Increased protein consumption helps to reduce the body proteins utilized –> resulting in higher portion of fat loss

 

lean protein sources girlonamission krissy boyd protein weight loss

 

Scientific Studies

Leidy, Carnell, Mattes, Campbell, 2007
  • Study of 46 women on calorie restricted diet
  • All classed as overweight or obese
  • 18% or 30% of intake from protein
  • All lost weight – combination of fat & lean body mass
  • Subjects on 30% protein diet
  • Felt fuller longer (satiety)
  • Improved blood lipid (fats & cholesterol) profile
  • Improved blood pressure & kidney function
  • Lost significantly less lean body mass –> weight loss was essentially more fat loss
  • More pleasurable diet experience –>  long term results

 

Weigle et al, 2005
  • 19 subject in a 12 week study
  • Protein intake compared 15% & 30% intake
  • Sustained decrease in “eating for pleasure”
  • Significant weight loss
  • No apparent increase in hunger

 

Lasker, Evans, Layman, 2008
  • 50 adults in 4 month weight loss trial
  • Calorie restricted diets w/ either 15% or 30% of intake from protein
  • Higher protein group:
  • Lost ~ 9% more weight
  • Reduced blood triglycerides (fats)
  • Increased “good” cholesterol

 

Protein & Weight Loss Over Time

  • Large scale European study of subjects who had already lost weight
  • Looked at weight loss maintenance over 6 months
  • Modest increase in protein intake resulted in better adherence to diet and maintenance of weight loss
  • (Larsen et al, 2010)

 

Protein & Weight Loss Maintenance

  • Additional protein intake (above 15% recommendation) limits weight regain that is commonly seen following weight loss diet
  • 113 overweight subjects in 6 month followup study
  • Much lower weight regain was seen and had a lower waist circumference than non-protein group
  • (Lejeune, Kovaks, & Westerterp-Plantega, 2004)

 

healthy salad

 

Safety of High Protein Diets

  • American Heart Association (2001) made statement that “Individuals who follow these [high protein] diets are at risk for potential cardiac, renal, bone, and liver abnormalities.”
  • But there is little, if any, evidence to support this claim (Manninen, 2004)

 

Protein has POSITIVE impact…(Manninen, 2004; Einstein et al, 2002)

  • No damage to healthy kidneys by higher protein
  • Consult doctor if impaired kidney function or diabetic
  • Positive influence on bone mineral density – promotes bone formation
  • Positive influence on blood pressure
  • Reduced risk of heart disease
  • Cholesterol & blood lipids
  • Protein promotes liver repair, reduces fatty liver

 

Azadbakht, Izadi, Surkan, Esmaillzadeh, 2013
  • 60 overweight and obese women
  • On calorie restricted diets for 3 months
  • 25% protein or 15% protein
  • High protein group saw:
  • Cholesterol, blood pressure decreased more significantly
  • More beneficial weight loss & reduced waist circumference
  • These are cardiovascular disease risk factors

 

Adding Protein In a Healthy Way

  • Many protein sources can come packaged along with unhealthy fats
  • “Lean” protein sources have more protein than fat –> they are “protein dense”
  • Don’t forget about vegetables!
  • Protein intake should not offset intake of other required food groups
  • Don’t forget about fibre!
  • It’s important that protein consumption is added mindfully to an overall healthy, balanced diet

 

Protein is a PART of a balanced diet
Protein is a PART of a balanced diet

 

Should You Use Protein Powders?

Advantages:
  • Convenient for situations of little time or on the go
  • Protein dense, with low amount of calories
  • Can be added to foods you already eat to amp up the protein level

 

Disadvantages:
  • May be nutritionally lacking – vitamins, minerals, etc
  • Can be costly

Simply put – a great addition to an already overall healthy diet, but shouldn’t be main source

 

 

Healthy High Protein Options

  • Chicken breast, skin removed, baked/not fried
  • Lean ground turkey
  • Egg whites
  • Low fat Greek yogurt
  • Low fat cheese
  • Extra lean beef (example, sirloin)
  • Edamame, soy, tofu
  • Lentils, legumes

Edamame

 

Example Meal Plan

 

Breakfast

¾ cup oats, ½ berries, ½ cup 0% Greek yogurt

 

Snack

1 oz low fat cheese & chopped raw vegetables

 

Lunch

Lean turkey sandwich on whole wheat bread with lettuce & mustard
1 hard boiled egg chopped on small salad
orange

 

Snack

Whole wheat crackers and ¼ cup hummus w/ red pepper slices

FN_skinless-chicken-thinkstock_s4x3

Dinner

Baked chicken breast (skin removed)
1 cup brown rice
2 cups mixed steamed vegetables (carrots, cauliflower, broccoli)

 

Conclusions

  • Protein is an important macronutrient
  • Protein intake can beneficially improve weight loss efforts in combination with a calorie restricted diet
  • Further, protein consumption can help to maintain weight loss over time
  • High protein diets have consistently been found to be safe for healthy adults & can improve health

 

References

Azadbakht, L., Izadi, V., Surkan, P. J., & Esmaillzadeh, A., (2013). Effect of high-protein weight loss diet on weight, high-sensitivity c-reactive protein, and cardiovascular risk among overweight and obese women: A parallel study. International Journal of Endocrinology, 2013, DOI: http://dx.doi.org/10.1155/2013/971724

Einstein, J., Roberts, S. B., Dallal, G., Saltzman, E. (2002). High-protein weight loss diets; Are they safe and do they work? A review of the experimental and epidemiological data. Nutrition Reviews 60,(7), 189-200.

Halton, T. L., & Hu, F. B. (2004). The effects of high protein diets on thermogenesis, satiety, & weight loss: A critical review. Journal of the American College of Nutrition, 23(5), 373-385.

Johnstone, A. M. (2009). High-protein diets for appetite control and weight loss – the “holy grail” of dieting? British Journal of Nutrition, 101, 1729-1730.

Larsen, T. M., Dalskov, S. M., van Baak, M., … Astrup A. (2010). Diets with high or low protein content and glycemic index for weight-loss maintenance. New England Journal of Medicine, 363, 2101-13.

Leidy, H. J., Carnell, N., Mattes, R. D., Campbell, W. W. (2007). Higher protein intake preserves lean mass and satiety with weight loss in pre-obese and obese women. Obesity, 15(2), 421-429.

Lejeune, M. P. G., Kovaks, E. M. R., & Westerterp-Plantega, M. S., (2005). Additional protein intake limits weight regain after weight loss in humans. British Journal of Nutrition, 93, 281-289.

Manninen, A. H. (2004). High-protein weight loss diets and purported adverse effects: Where is the evidence? Sports Nutrition Review Journal, 1(1), 45-51.

Walker Lasker, D. A., Evans, E. M., Layman, D. K. (2013). 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, 5(3), DOI: 10.1186/1743-7075-5-30

Weigle, D. S., Breen, P. A., Matthys, C. C et al. (2005). A high protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations. Am J Clin Nutr, 82, 41-48.

 

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