Strength and Fitness Uk.com - The Impartial Guide to strength, fitness, endurance and nutrition

Protein For Weight Loss

High protein diets and weight loss

High protein diets have become increasingly popular in recent years with advocates claiming they are more beneficial for weight loss and preservation of muscle mass than traditional calorie restriction diets. Essentially a high-protein diet is one in which the proportion of calories from protein is increased from the normal 15-20% to 30% or more of total calories. Research suggests that a high protein diet – particularly high quality protein – may be beneficial for weight loss/weight management (McIver et al., 2012; Josse et al., 2011; Fletcher-Mors et al., 2010; Brinkworth et al., 2009; Evangelista et al., 2009; Lasker et al., 2008; Keogh et al., 2007; Noakes et al., 2005; Labayen et al., 2003; Baba et al., 1999;). Importantly a high protein diet can help to preserve muscle mass when dieting – this is important because any loss of muscle mass has a negative effect on metabolism/metabolic rate.

What are proteins and why are they important?

Proteins play a vital role in the human body where they are essential for processes involved in growth and maintenance of all cells, structural components (bones, ligaments etc), and organs. The proportion of proteins in the human body can vary dependent on body composition e.g. someone with lower body fat will have a higher % protein content than someone with a higher body fat. Proteins are particularly abundant in muscle tissue where they make up approximately 20 per cent of the total muscle mass.

Proteins can also be metabolised aerobically as an energy source providing 4 calories per gram (Fat provides 9 calories per gram) – the proportion of aerobic metabolism of proteins is fairly low however this can increase significantly during periods of carbohydrate depletion (low carbohydrate diets, prolonged endurance exercise, malnutrition etc). The increased rates of aerobic breakdown of proteins when dieting can significantly decrease total muscle mass and lead to reduced metabolism – lean muscle mass is a key contributor to metabolic rate. Decreased muscle mass and the subsequent reduction in metabolic rate is one of the reasons why the rate of weight loss, and hence the effectiveness of the diet, decreases over time. Proponents of the high protein diet suggest say that the increased protein intake helps to preserve lean muscle mass and protect against reductions in metabolic rate.

Benefits of a high protein diet for weight loss

A good protein intake appears to have a number of beneficial effects that can influence weight loss including: 1) reduced appetite - primarily by increasing satiety levels (the state of feeling full) (Weigle et al., 2011) ; 2)helps to preserve/increase lean muscle mass when dieting or dieting and exercising (McIver et al., 2012; Josse et al., 2011) - important since muscle mass is one of the key factors that influence resting metabolic rate and therefore any decrease in muscle mass (like when dieting) can lead to reduced metabolism/metabolic rate and will have a negative effect on weight loss ; 3) Helps to promote an increased loss of visceral fat (Josse et al., 2011) - a type of fat located in the abdominal cavity and around organs; 4) Increased leptin sensitivity (Weigle et al., 2005; Du et al., 2000) - this is important since obesity is linked to leptin resistance .

How much protein is required for weight loss?

The recommended protein intake for a high protein diet is currently considered to be a protein intake that comprises around 30% of total calories*, with around 40-50% of calories** coming from carbohydrate and 20-30% or less coming from fat*** (McIver et al., 2012).  A standard/traditional diet would normally involve a protein intake that comprises around 15% of total calories, with approximately 55% of calories coming from carbohydrate and 30% from fat.

 *1 gram of protein = 4 calories, **1 gram of carbohydrate = 4 calories, ***1 gram of fat = 4 calories

High Protein diet (30% Protein / 50% Carbohydrate / 20% Fat) 

Calories / Day Protein (g)/day
30% of calories
Carbohydrate (g)/day
50% of calories
Fat (g)/day
20% of calories
1000 Calorie/day diet  75g (300 calories)  125g (500 calories)  22g (200 calories)
1100 Calorie/day diet  82.5g (330 calories)  137.5g (550 calories)  24.5g (220 calories)
1200 Calorie/day diet  90g (360 calories)  150g (600 calories)  27g (240 calories)
1300 Calorie/day diet  97.5g (390 calories)  162.5g (650 calories)  29g (260 calories)
1400 Calorie/day diet  105g (420 calories)  175g (700 calories)  31g (280 calories)
1500 Calorie/day diet  112.5g (450 calories)  187.5g (750 calories)  33g (300 calories)
1600 Calorie/day diet  120g (480 calories)  200g (800 calories)  35.5g (320 calories)
1700 Calorie/day diet  127.5g (510 calories)  212.5g (850 calories)  38g (340 calories)
1800 Calorie/day diet  135g (540 calories)  225g (900 calories)  40g (360 calories)

 

High Protein diet (30% Protein / 40% Carbohydrate / 30% Fat) 

Calories / Day Protein (g)/day
30% of calories
Carbohydrate (g)/day
40% of calories
Fat (g)/day
30% of calories
1000 Calorie/day diet  75g (300 calories)  100g (400 calories)  33g (300 calories)
1100 Calorie/day diet  82.5g (330 calories)  110g (440 calories)  36.5g (330 calories)
1200 Calorie/day diet  90g (360 calories)  120g (480 calories)  40g (360 calories)
1300 Calorie/day diet  97.5g (390 calories)  130g (520 calories)  43g (390 calories)
1400 Calorie/day diet  105g (420 calories)  140g (560 calories)  46.5g (420 calories)
1500 Calorie/day diet  112.5g (450 calories)  150g (600 calories)  50g (450 calories)
1600 Calorie/day diet  120g (480 calories)  160g (640 calories)  53g (480 calories)
1700 Calorie/day diet  127.5g (510 calories)  170g (680 calories)  56.5g (510 calories)
1800 Calorie/day diet  135g (540 calories)  180g (720 calories)  60g (540 calories)

 

Traditional diet (15% protein / 55% Carbohydrate / 30% Fat) 

Calories / Day Protein (g)/day
15% of calories
Carbohydrate (g)/day
55% of calories
Fat (g)/day
30% of calories
1000 Calorie/day diet  37.5g (150 calories)  137.5g (550 calories)  33g (300 calories)
1100 Calorie/day diet  41g (165 calories)  151g (605 calories)  36.5g (330 calories)
1200 Calorie/day diet  45g (180 calories)  165g (660 calories)  40g (360 calories)
1300 Calorie/day diet  49g (195 calories)  179g (715 calories)  43g (390 calories)
1400 Calorie/day diet  52.5g (210 calories)  192.5g (770 calories)  46.5g (420 calories)
1500 Calorie/day diet  56g (225 calories)  206g (825 calories)  50g (450 calories)
1600 Calorie/day diet  60g (240 calories)  220g (880 calories)  53g (480 calories)
1700 Calorie/day diet  64g (255 calories)  234g (935 calories)  56.5g (510 calories)
1800 Calorie/day diet  67.5g (270 calories)  247.5g (990 calories)  60g (540 calories)

Is a high protein diet effective for weight loss?

Allthough there are a large number of studies that have found high protein diets to be more effective than traditional diets (Josse et al., 2011; Fletcher-Mors et al., 2010; Brinkworth et al., 2009; Evangelista et al., 2009; Lasker et al., 2008; Keogh et al., 2007;Noakes et al., 2005; Labayen et al., 2003; Baba et al., 1999;) there have also been a number of studies that have failed to find significantly improved weight loss with high protein diets (Clifton et al., 2008; Leidy et al., 2007; Kleiner et al., 2006; Brinkworth et al., 2004; Due et al., 2004; Stamets et al., 2004; Farnsworth et al., 2003; Lanscombe et al., 2003;). A number of the studies that failed to find a significant different in weight loss with high protein diet were longer term studies and this has led to the suggestion that there may be a diminished weight loss with the long term use of a high protein diet (Lepe et al., 2011). Despite the mixed results most studies have generally found increased weight loss - even if not always significantly increased weight loss - with high protein diets. In addition a high protein diet can help to improve blood fat levels and maintain/improve levels of HDL-cholesterol - the good cholesterol.

Are high protein diets safe?

 High protein diets are generally considered safe and free of serious side effects. However concerns have been raised about the risk of kidney damage due to the diuretic effect of a low carbohydrate intake which can place stress on the kidneys. Dispite this a high protein content is generally considered safe (at least in the short term) providing you do not suffer with kidney or liver disease.

Concerns have been raised about increased LDL cholesterol levels, due to the way many of these high protein diets encourage an increased consumption of animal proteins, some of which are high in saturated fats which can increase levels of LDL cholesterol. This risk can be reduced by consuming healthier sources of protein such as whey protein drinks, skimmed milk, chicken, turkey, tuna, salmon etc. A further concern is that many of these diets encourage a reduced consumption of vegetables and fruit, due to their carbohydrate content, which can lead to reduced intake of anti-oxidants, vitamins, minerals, fibre and can further negatively effect cholesterol levels. 

What are the best sources of quality protein

When you are considering the best sources of protein for a high protein diet you need to consider two main factors:

1) The quality of the protein within the food - protein is made up of a number of amino acids, some of which are essential (they cannot be manufactured by the body) and some are non-essential (these can be manufactured from other amino acids within the body) - high quality proteins contain a broad spectrum of amino acids but are particularly high in essential amino acids like the branched chain amino acids (BCAAs) leucine, isoleucine and valine. The BCAAs are believed to be particularly effective at maintaining muscle mass, improving metabolism and maintaining a healthy immune system. It's important to remember that unlike animal proteins, plant sources of protein do not provide a complete source of amino acids and therefore vegetarians need to consume a variety of plant sources of protein.

2) The proportion of fat that is present within the protein source can impact on the benefits of that protein. Some foods can be a good source of protein but come with the negative that they are high in fats and saturate fats and so excessive consumption of these may have an adverse effect on dieting or health - examples of these include: processes meats (e.g. sausages), bacon, beef mince, cheese

Good low/reduced fat sources of animal protein include: Cod, haddock, tuna, salmon, sea bass, turkey breast, chicken breast, turkey mince, lean beef mince, ham slices, chicken slices, skimmed milk, cottage cheese

Good vegetarian/plant sources sources of protein include: quorn and soya mince, chick peas, kidney beans, butter/lima beans, lentils, garden peas/petit pois, mangetout, brocholli, swetcorn

Protein weight loss summary:

  • 1) High protein diets are believed to be more beneficial for weight loss than traditional diets
  • 2) An increased protein intake is believed to help to maintain/preserve muscle mass whilst dieting which can help to maintain metabolic rate
  • 3) Proteins are essential for health and play key roles in growth and maintenance of all cells, structural components and organs
  • 4) Proteins acan be metabolised aerobically during periods of carbohydrate depletion such as when dieting or during prolonged aerobic exercise. This can lead to increased muscle breakdown and reduced metabolism.
  • 5) A high protein diet is considered to be one in which 30% or more of total calories are from protein.
  • 6) Research is not fully conclusive regarding the benefits of high protein diets compared with traditional diets. Some research suggests that the benefits of a high protein diet may diminish over time.
  • 7) High protein diets are generally considered safe but should be avoided by those with kidney or liver disease. Some concerns have been raised about LDL-cholesterol levels due to the high fat content of some high protein meats consumed with some of these diets.
  • 8) When considering the best protein sources for high protein diets you should consider the quality of the protein and the fat content of the protein source
  • 9) Good low fat protein sources include: turkey, chicken, lean beef, tuna, cod, milk, cottage cheese, quorn, soya, chick peas, kidney beans, butter beans, lentils, peas, and beans.

Protein for weight loss references:

Baba NH, Sawaya S, Torbay N, Habbal Z, Azar S, Hashim SA (1999) High protein vs high carbohydrate hypoenergetic diet for the treatment of obese hyperinsulinemic subjects.Int J Obes Relat Metab Disord 1999, 23:1202–1206.

Brinkworth GD, Noakes M, Buckley JD, Keogh JB, Clifton PM. (2009) Long-term effects of a very-low-carbohydrate weight loss diet compared with an isocaloric low-fat diet after 12 mo. Am J Clin Nutr 2009; 90 (1): 23-32.

Brinkworth GD, Noakes M, Parker B, Foster P, Clifton PM. (2004) Long-term effects of advice to consume a high-protein, low-fat diet, rather than a conventional weight-loss diet, in obese adults with Type 2 diabetes: one-year follow-up of a randomised trial. Diabetologia 2004; 47 (10): 1677-86.

Clifton PM, Keogh JB, Noakes M.(2008) Long-term effects of a highprotein weight-loss diet. The American Journal of Clinical Nutrition 2008; 87 (1): 23-9.

Du F, Higginbotham DA, White BD. (2000) Food intake, energy balance and serum leptin concentrations in rats fed low-protein diets.J Nutr. 2000 Mar;130(3):514-21.

Due A, Toubro S, Skov AR, Astrup A. (2004) Effect of normal-fat diets, either medium or high in protein, on body weight in overweight subjects: a randomised 1-year trial. Int J Obes Relat Metab Disord 2004; 28 (10): 1283-90.

Evangelista LS, Heber D, Li Z, Bowerman S, Hamilton MA, Fonarow GC (2009) Reduced body weight and adiposity with a high-protein diet improves functional status, lipid profiles, glycemic control, and quality of life in patients with heart failure: a feasibility study. J Cardiovasc Nurs 2009, 24:207–215.

Farnsworth E, Luscombe ND, Noakes M, Wittert G, Argyiou E, Clifton PM (2003) Effect of a high-protein, energy-restricted diet on body composition, glycemic control, and lipid concentrations in overweight and obese hyperinsulinemic men and women. Am J Clin Nutr 2003, 78:31–39.

Flechtner-Mors M, Boehm BO, Wittmann R, Thoma U, Ditschuneit HH (2010) Enhanced weight loss with protein-enriched meal replacements in subjects with the metabolic syndrome. Diabetes Metab Res Rev 2010, 26:393–405.

Josse AR, Atkinson SA, Tarnopolsky MA, Phillips SM.(2011) Increased consumption of dairy foods and protein during diet- and exercise-induced weight loss promotes fat mass loss and lean mass gain in overweight and obese premenopausal women.J Nutr. 2011 Sep;141(9):1626-34. Epub 2011 Jul 20.

Keogh JB, Luscombe-Marsh ND, Noakes M, Wittert GA, Clifton PM. (2007) Long-term weight maintenance and cardiovascular risk factors are not different following weight loss on carbohydrate-restricted diets high in either monounsaturated fat or protein in obese hyperinsulinaemic men and women. British Journal of Nutrition 2007; 97 (02): 405-10

Kleiner RE, Hutchins AM, Johnston CS, Swan PD (2006) Effects of an 8-week high-protein or high-carbohydrate diet in adults with hyperinsulinemia. MedGenMed 2006, 8:39.

Labayen I, Diez N, Gonzalez A, Parra D, Martinez JA (2003) Effects of protein vs. carbohydrate-rich diets on fuel utilisation in obese women during weight loss. Forum Nutr 2003, 56:168–170.

Lasker DA, Evans EM, Layman DK (2008) 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. Nutr Metab (Lond) 2008, 5:30.

Leidy HJ, Carnell NS, Mattes RD, Campbell WW (2007) Higher protein intake preserves lean mass and satiety with weight loss in pre-obese and obese women. Obesity (Silver Spring) 2007, 15:421–429.

Lepe M, Bacardí Gascón M, Jiménez Cruz A.(2011) Long-term efficacy of high-protein diets: a systematic review. Nutr Hosp. 2011 Nov-Dec;26(6):1256-9.

Luscombe ND, Clifton PM, Noakes M, Farnsworth E, Wittert G (2003) Effect of a highprotein, energy-restricted diet on weight loss and energy expenditure after weight stabilization in hyperinsulinemic subjects. Int J Obes Relat Metab Disord 2003, 27:582–590.

Noakes M, Keogh JB, Foster PR, Clifton PM (2005) Effect of an energy-restricted, highprotein, low-fat diet relative to a conventional high-carbohydrate, low-fat diet on weight loss, body composition, nutritional status, and markers of cardiovascular health in obese women. Am J Clin Nutr 2005, 81:1298–1306

McIver CM, Wycherley TP, Clifton PM. (2012) MTOR signaling and ubiquitin-proteosome gene expression in the preservation of fat free mass following high protein, calorie restricted weight loss. Nutr Metab (Lond). 2012 Sep 14;9(1):83. [Epub ahead of print]

Stamets K, Taylor DS, Kunselman A, Demers LM, Pelkman CL, Legro RS (2004) A randomized trial of the effects of two types of short-term hypocaloric diets on weight loss in women with polycystic ovary syndrome. Fertil Steril 2004, 81:630–637.

Weigle DS, Breen PA, Matthys CC, Callahan HS, Meeuws KE, Burden VR, Purnell JQ.(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. 2005 Jul;82(1):41-8.