Protein and Weight Loss

If your goal is to lose weight, then protein is your best friend. You don’t need to restrict your diet or starve yourself to shed those pounds - it’s all about changing what you eat. Different types of food are metabolised in different ways, and this can be an important factor in a weight-loss protocol.

Increasing the amount of protein you eat as part of your calorie-controlled diet may make it easier to lose those unwanted pounds. You should still aim to eat the correct amount of calories each day, but if more of these calories are made up of protein, then they’ll work more efficiently for your weight loss goals. The good news is that high-protein foods are typically, appetising, delicious, and filling, so making this change should actually make your diet more enjoyable! 

If you're not sure how many calories you should be eating to lose weight in a healthy, balanced way, you can find some helpful advice in our article about calories in/calories out. However, if you're looking to lose a significant amount of weight, it's always a good idea to have a chat with your doctor or health professional first. 

In this article, we'll look at why protein is such a weight-loss superhero, how much additional protein you should be eating, and which foods you should be adding to your diet.

Read on to find out how increasing your protein intake could help you reach your weight loss goals more easily.

How does protein help you lose weight?

Firstly, it’s important to note that protein is not a weight loss supplement or diet pill, it is actually a vital nutrient for the body, found naturally in our diet. It is essential for a huge number of body functions, including growth, repair, and maintenance of body tissues, immune function, hormone synthesis, enzymic function, and a source of energy.

Read our article for more information about the benefits of protein.

But how does eating more protein help with weight loss? You may be surprised to learn that there are numerous different modes of action by which protein helps to regulate weight loss and gain in the body.

There are numerous ways in which protein could aid weight loss

Let’s look at these actions in more detail:

  • Protein regulates weight loss hormones

Certain hormones in the body have an effect on weight loss or gain, by promoting satiety or regulating body fat distribution and metabolism. High protein intake has been shown to increase the production of, and sensitivity to, hormones such as glucagon-like peptide-1, cholecystokinin, and peptide tyrosine-tyrosine which tell your body that it’s full and so reduce your appetite. This means you’re less likely to snack on extra calories in between meals (1,2,3).

  • Protein makes you feel fuller for longer

As well as promoting the production of satiety hormones, protein also decreases the production of the hormone ghrelin, known as the ‘hunger hormone’ because it promotes appetite. Ghrelin is produced in the gut when the stomach is empty, but a higher protein intake actually results in prolonged suppression of ghrelin, which therefore reduces your desire to eat. In these ways protein helps to keep you feeling full and stops you eating more than your recommended daily calorie intake (4).

  • Protein boosts metabolism

Metabolism is the term used to describe the bodily functions that turn food into energy and use calories. A fast metabolism burns calories more quickly both at rest or during activity. Protein helps to increase the rate of both resting and active metabolism because it has a high thermic effect.The thermic effect of food relates to the amount of energy required to digest it, also called diet-induced thermogenesis (DIT). A food’s thermic effect is calculated by working out the increase in energy expenditure above basal fasting rate, also known as resting metabolic rate, divided by the energy content of the food (5,6). The result is given as a percentage. This metabolic response to food varies according to the type of food consumed. Protein has the highest thermic effect of any food - around 30%, compared to around 3% for fat and 8% for carbohydrates (7). This means that only 70% of the calories in protein remain to be used as energy or stored as fat.

  • Protein preserves muscle mass and prevents you regaining weight

When dieting, we lose muscle mass as well as fat, often amounting to as much as 25% of weight lost. This is not ideal, as muscle is essential for overall well being, giving us energy and strength and playing a part in many bodily processes. It’s also more difficult to restore muscle than fat, and low muscle mass can slow down metabolism and predispose dieters to regain weight. Protein supplies amino acids, the building blocks for muscle development and maintenance, so a high-protein diet can help to preserve muscle mass during a weight loss programme (8), and prevent weight regain (9). A high-protein diet will help to support muscle mass best in conjunction with a programme of regular exercise.

  • Protein regulates blood sugar and stops cravings

Eating carbohydrates has a direct effect on our blood sugar levels. If we eat a lot of quickly metabolised refined carbohydrates and sugary foods, this can cause blood sugar peaks and troughs. This is bad news when dieting, as low blood sugar can cause you to crave more sugary, high-calorie foods, and it can become a vicious cycle. Increasing the amount of protein you eat can help to break this cycle. Protein breaks down very slowly during digestion so has a minimal effect on blood glucose levels, and it actually helps to regulate blood sugar by also slowing the absorption of carbs. This helps to keep you feeling fuller for longer and prevents those blood sugar crashes which have you reaching for quick fix sugary snacks and empty calories.

A high-protein diet works best in combination with a regular exercise programme

How much protein should I eat when dieting?

The recommended daily intake (RNI) of protein for adults is around 0.6-0.8g of protein per kg of body weight each day(9). However, this is now considered to be a conservative estimate, and really just the bare minimum we need to support bodily functions. Our optimum protein intake can actually vary quite considerably for each individual, depending on their age, lifestyle, gender, weight and fitness level. When dieting, a more realistic recommendation would be for around 35% of your daily calorie intake to be from protein, or around 1.6g -2g per kg of body weight each day, especially if you’re also exercising regularly (10).

For more information about optimum protein intake, read our article How much protein do I need?

You aim to consume protein with every meal, and ideally at snack times too. Once you know which foods are good protein sources, then it becomes easier to include them in your diet.

Find out how to get more good quality protein in your diet in the next section.

Best high protein foods for weight loss

Proteins are made up of molecules called amino acids. There are 22 essential amino acids, and the body can synthesise some of these itself. However, there are 9 essential amino acids which must be sourced from the diet each day. All animal-based protein sources and some plant-based sources contain all of these 9 amino acids; however, some plant-based foods only contain a few of them. This means that vegans should take care to eat and combine a wide variety of plant proteins to ensure that they consume a full complement of amino acids each day.

Animal-based sources of protein:

  • Meat
  • Poultry
  • Fish

Vegetarian sources of protein:

  • Milk
  • Cheese
  • Yoghurt
  • Eggs

Vegan sources of protein:

  • Tofu, tempeh and other soy products
  • Tree nuts and peanuts
  • Seeds such as hemp, sunflower, pumpkin, quinoa and chia
  • Pulses such as beans, chickpeas, lentils and peas
  • Whole grains
  • Nutritional yeast
  • Spirulina

You can also get protein from supplements, but unless you’re an elite athlete trying to build muscle, there’s usually no need to take protein powders, protein drinks or supplements for weight loss. It’s better to take your daily calories in the form of nutritious meals, just with an increased ratio of protein. If you hate cooking or find it difficult to work out how much protein you should be eating, consider subscribing to a healthy, high-protein meal prep service designed to support weight loss. Having ready-prepared meals will help you to avoid reaching for unhealthy snacks when you’re in a hurry, plus the correct macros will be worked out for you, so you’ll have more time to focus on your supporting exercise programme.

By simply increasing your protein intake, you can have a tasty, filling, and nutritious diet menu which should not only help you lose weight but help you to maintain your desired weight long-term.

So don’t eat less, eat smart, and you can smash those weight loss goals!

If you enjoyed this article you may like to read some of these other related articles:

The Benefits of Protein

Can Protein Help Support Mental Health?

How Much Protein Do I Need?

How to Stay Fit if You Sit 9-5



References:

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  2. Wang L, Jacobs JP, Lagishetty V, Yuan PQ, Wu SV, Million M, Reeve JR Jr, Pisegna JR, Taché Y (.2017) High-protein diet improves sensitivity to cholecystokinin and shifts the cecal microbiome without altering brain inflammation in diet-induced obesity in rats. Am J Physiol Regul Integr Comp Physiol. Oct 1;313(4):R473-R486. doi: 10.1152/ajpregu.00105.2017. Epub 2017 Jul 19. PMID: 28724546; PMCID: PMC5668619.
  3. Stentz FB, Mikhael A, Kineish O, Christman J, Sands C.(2021) High protein diet leads to prediabetes remission and positive changes in incretins and cardiovascular risk factors. Nutr Metab Cardiovasc Dis. Apr 9;31(4):1227-1237. doi: 10.1016/j.numecd.2020.11.027. Epub 2020 Dec 8. PMID: 33549435.
  4. Chrysi Koliaki, Alexander Kokkinos, Nicholas Tentolouris, Nicholas Katsilambros, "The Effect of Ingested Macronutrients on Postprandial Ghrelin Response: A Critical Review of Existing Literature Data", International Journal of Peptides, vol. 2010, Article ID 710852, 9 pages, 2010. https://doi.org/10.1155/2010/710852 ://www.nutrition.org.uk/healthy-sustainable-d... (Accessed: 17 November 2023).
  5. Westerterp, K.R. Diet induced thermogenesis. (2004). Nutr Metab (Lond) 1, 5 https://doi.org/10.1186/1743-7075-1-5
  6. Halton TL, Hu FB. (2004) The effects of high protein diets on thermogenesis, satiety and weight loss: a critical review. J Am Coll Nutr. Oct;23(5):373-85. doi: 10.1080/07315724.2004.10719381. PMID: 15466943.
  7. Westerterp KR.( 2004) Diet induced thermogenesis. Nutr Metab (Lond). Aug 18;1(1):5. doi: 10.1186/1743-7075-1-5. PMID: 15507147; PMCID: PMC524030.
  8. Cava E, Yeat NC, Mittendorfer B.( 2017) Preserving Healthy Muscle during Weight Loss. Adv Nutr. May 15;8(3):511-519. doi: 10.3945/an.116.014506. PMID: 28507015; PMCID: PMC5421125.
  9. Moon J, Koh G. (2020) Clinical Evidence and Mechanisms of High-Protein Diet-Induced Weight Loss. J Obes Metab Syndr. Sep 30;29(3):166-173. doi: 10.7570/jomes20028. PMID: 32699189; PMCID: PMC7539343.
  10. Wu G. Dietary protein intake and human health. 2016 Food Funct. Mar;7(3):1251-65. doi: 10.1039/c5fo01530h. PMID: 26797090.

Posted in Health on by Kerry Beeson BSc (Nut Med) Nutritional Therapist & Metabolic Balance Coach