So how does protein help with weight loss?
Based on an article by Pesta and colleagues, protein can provide a double benefit of preventing satiety and reducing fat mass. The mechanism behind the satiety claim involves the secretion of satiety hormones known as GIP & GLP-1, these are hormones known as incretins that regulates and decreases glucose levels in the blood. These hormones are released after eating and could reduce gastric emptying which may directly reduce food intake (due to increased satiety).
Aside from the effects of the satiety hormones, there are research indicating that high protein diets may directly promote a satiety response. A study by Plantenga et al revealed that a significant increase in 24-hour satiety in subject consuming a high-protein diet compared to a high fat diet. A proposed mechanism was documented by Nefti et al indicating that a high intake of protein induces a vagal feedback to the satiety centre in the brainstem and the hypothalamus to directly suppress hunger.
The mechanism behind the other benefit (reducing fat mass) with a high protein diet involves a term called “Diet-induced thermogenesis (DIT) or the thermic effect of food, putting it simplistically, it is the metabolic response towards food intake. It is shown in multiple studies that a high DIT of protein affects energy balance. Whitehead et al. conducted a study measuring 24-hour energy expenditure of subjects on a high protein diet (36% daily energy from protein) against two separate groups with 15% daily energy from protein (One high in carbohydrate and the other in fat). The study indicated, energy expenditure was around 300 kJ/day higher in subjects consuming the high-protein diet, in which we could conclude that a high protein diet is associated with an increased 24-hour diet induced energy expenditure. And this is ultimately what leads to a reduced fat mass and increased weight loss effect.
Is it crucial to have it in my exercise and diet regimen?
Armed with the above information, it is prudent for you to know that you do not only embark on a quest to consume as much protein from your diet for a weight loss effect, but rather, you should combine this with an adequate amount of strength or resistance training.
In many situations, many folks who tries to lose weight also ends up losing muscle mass. With a decrease in muscle mass, you may also see a decrease in metabolic rate (not the ideal scenario!). It has been a well- documented fact that resistance training is also a major factor in reducing the rate of muscle loss and metabolic slowdown when you are trying to lose weight.
Hence, it is crucial that you couple your high-protein diet with a sufficient amount of resistance exercise weekly training regimen. Not only does these two factors ensure that your metabolic rate remains high, it also ensures that you would actually look fit and lean instead of being in a state of “skinny-fat”(Being skinny but with low muscle mass, therefore, low metabolic rate)
Another quick fact to share is that high protein diet without a proper exercise regimen will simply lead to the excess protein accumulating as fat within your body. (Which is definitely not the ideal situation!!!)
What do I need to eat to get enough protein for weight loss?
Your diet should be full of protein-rich food such as poultry (chicken/turkey), lean beef or pork (notice the term ‘lean’). In addition, fish is also a good choice of protein-rich food (e.g. salmon haddock, trout, etc.). Do not leave out the plant based high-protein food as well, such as peas, kidney beans, lentils, edamame etc. Plant based food are also rich in phytonutrients or plant nutrients which is a crucial component for your body to recover and build muscles after your workout sessions. One other quick and cheap source of protein will be from eggs (any type).
As with all types of food, always be weary of how the food is prepared (avoid oily and fried food) and the amount of fat content along with the high-protein meal you are consuming. This is one of the reasons why some would claim that they are on a high-protein diet but can’t seem to lose weight. These folks are consuming fried chicken or fish and chips as a source of ‘protein’, it is likely high in protein but likely also high in fat content as well! Furthermore, if there is an inadequate amount of exercise done during the week, no amount of high-protein food will aid with the weight loss goal! So stick to the principles of eating lean protein-rich food and exercising regularly for maximal weight loss effects!
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Pesta DH, Samuel VT et al. A high protein diet for reducing body fat: mechanisms and possible caveats. Nutr Metab (Lond). 2014; 11-53.
Whitehead JM, McNeill G, et al. The effect of protein intake on 24-h energy expenditure during energy restriction. Int J Obes Relat Metab Disord. 1996;20:727–732.
Westerterp-Plantenga MS, Rolland V, Wilson SA, Westerterp KR. Satiety related to 24 h diet-induced thermogenesis during high protein/carbohydrate vs high fat diets measured in a respiration chamber. Eur J Clin Nutr. 1999;53:495–502. doi: 10.1038/sj.ejcn.1600782
Nefti W, Darcel N, Fromentin G, Tomé D. Long term exposure to high protein diet or high fat diet have opposite effects on vagal afferent sensitivity to lumenal macronutrients and ip cholecystokinin. FASEB J. 2007;21:367.7. doi: 10.1096/fj.07-8582com