Diet, Diet, Diet, Diet, Weight loss, Weight loss, Protein, Fat loss, Fat loss, Weight loss, Slimming, Weight loss

In this article we answer how much protein one needs for successful, long-term weight management!

At our previous article on protein, we have seen that increasing or maintaining the amount of protein helps to maintain a diet, which is reflected in studies showing that maintaining lean mass is crucial to maintaining weight loss.

Time to go deeper and give concrete advice.

Diet, Diet, Diet, Diet, Weight loss, Weight loss, Protein, Fat loss, Fat loss, Weight loss, Slimming, Weight loss


Popular diets aimed at weight loss are often rather extreme in their macronutrient composition, which makes long-term adherence difficult.

This often translates into high wear/breakage rates (e.g. 35-50% of people dropped out of the one-year study on Atkins, Zone, Ornish or Weight Watchers diets), but also by gradually decreasing compliance to the diet over time.

Wear rates are usually much lower for diets with less extreme macronutrient compositions. For example, 21% of subjects dropped out of the DIETFITS test, which lasted 1 year, whose aim was to examine the effects of healthy low-fat or low-carbohydrate diets.

The 16-26% of the participants left the 2 years POUNDS Lost test (diets provided 15-25% of energy as protein, 20-40% as fat and 35-65% as carbohydrate), while 10-22% of subjects gave up two-year DIRECT test (which looked at three diets: a low-fat diet as recommended by the American Heart Association, a Mediterranean diet or a less restrictive low-carbohydrate/high-protein Atkins diet).

To call a spade a spade, the progressive decrease in compliance over time is a common feature of any dietary intervention, no matter how moderate or extreme.

For example, reviewing the research comparing Atkins, Zone, Ornish and Weight Watchers, dietary adherence scores were directly correlated with changes in body weight, and this relationship was almost identical for all four popular diets tested.

More specifically, low to moderate compliance was associated with weight loss, but from moderate compliance and above, body weight decreased in a nearly linear fashion, such that the best compliant subjects lost approximately 7% of body weight after 1 year, compared to an average weight loss of 2-3% for the entire group.

Something similar can be observed in the test POUNDS Lost, where the number of group sessions attended by participants (as an indicator of their compliance with the dietary intervention) was a positive factor in weight loss over the 2-year study period (about 0.2 kg more weight loss for each session) and indeed this relationship was not different between the four diet groups (low or high protein and fat).

In a subsequent data analysis of the same study, indicators of protein intake in all participants (i.e. not just those on high-protein diets) suggested that a greater increase in protein intake from the start of the intervention had positive effects on long-term weight loss.

These observations place nutritional compliance as a primary factor in a successful diet rather than macronutrient composition in terms of long-term weight loss success.

Any diet can be successful as long as it is followed, which is perhaps not surprising.

Another important predictor of a successful weight loss intervention, regardless of diet composition, appears to be the initial rate of weight loss, as shown in here and here.

The results from the study Look AHEAD in overweight and obese people with type 2 diabetes showed that weight change in the first month or two months of intervention was a predictor of weight loss after 4 and 8 years.

These observations are probably not related to differences in adherence so early in the dietary intervention (adherence is usually excellent in the first few weeks), but may instead reflect certain physiological or behavioural characteristics of people who succeed in losing weight.

Diet, Diet, Diet, Diet, Weight loss, Weight loss, Protein, Fat loss, Fat loss, Weight loss, Slimming, Weight loss


In this meta-analysis found that simply recommending higher protein consumption during the weight maintenance phase had small but significant effects on body weight and fat mass compared to recommending normal protein consumption or a standard diet.

Among the larger trials that evaluated the effectiveness of high-protein diets in maintaining weight loss were the DIOGENES, a large randomised controlled trial conducted in eight European countries.

In this trial, after a period of dieting for weight loss, a high-protein diet was associated with less weight regain of about one kilogram after a period of six months. A low glycaemic index diet had similar results.

At the end of the study (total attrition rate: 29%), no significant weight regain was observed in the high-protein/low glycemic index diet group, the high-protein/high glycemic index diet group, or the low-protein/low glycemic index diet group.

Only the diet combining low protein and high glycaemic index was associated with significant weight regain after a period of weight loss.

Diet, Diet, Diet, Diet, Weight loss, Weight loss, Protein, Fat loss, Fat loss, Weight loss, Slimming, Weight loss
Weight recovery in diets with different protein content and glycemic index (GI) in the DIOGENES trial. Source: Magkos F. The role of dietary protein in obesity. rev Endocr Metab Disord. 2020 Sep;21(3):329-340. doi: 10.1007/s11154-020-09576-3. PMID: 32740867.

In a short-term (6 months) but well-controlled randomized trial, the GLYNDIET, 82 overweight and obese subjects were placed on a diet with a moderate macronutrient composition (40%, 42% and 18% of total energy as fat, carbohydrate and protein, respectively) that had either a low or high glycaemic index.

Discontinuation rates were low (approximately 10% and 12%, respectively), the weight loss trajectory was similar, and the final weight loss after 6 months was not significantly different between the low and high glycemic index diets.

Given that the 28-point difference in glycaemic index in GLYNDIET had no significant effect on weight change over 6 months, whereas the 7-point difference in glycaemic index appeared to have an effect on weight regain over the same time period in the DIOGENES study, this probably means that the latter results should be interpreted with caution.

In fact, in two DIOGENES study centres (Maastricht and Copenhagen), monitoring repeated at 12 months and, despite the small number of subjects evaluated, it was observed that high-protein diets were still associated with weight regain of about 2 kg less than low-protein diets, but the glycaemic index of the diet was no longer associated with weight regain.

The average weight regain at 12 months was about 35% of the initial weight loss and the subjects who regained the least weight were, in fact, those in the group that combined the high-protein, high-glycemic index diet.

Thus, we see that while there is indeed evidence to support a role for increased protein intake in the diet in terms of successful weight loss maintenance, the importance of the glycaemic index is questionable.

Perhaps the big factor influencing the results is the fibre and not the glycaemic index per se.

It seems that the combination of a low glycaemic index and high protein diet can be senior when such a diet offers more fibre, which has been shown to stimulates cholecystokinin, a key hormone involved in digestion and serves as a an anorexigenic agent that helps finish a meal.

Also, short-chain fatty acids can be produced during fibre metabolism in the large intestine, further promoting the secretion of glycagonomorphic peptide 1 (GLP-1) and peptide YY (PYY), which can also help control appetite.

That said, in the study PREVIEW, during a three-year maintenance phase after weight loss, the diet combining high protein consumption and low glycaemic index was superior in suppressing hunger compared to the moderate protein and glycaemic index diet, but this did not translate into a difference in weight regain.

It may therefore be that maintaining such high protein intakes combined with a low glycaemic index may be difficult to maintain in the long term.

Diet, Diet, Diet, Diet, Weight loss, Weight loss, Protein, Fat loss, Fat loss, Weight loss, Slimming, Weight loss


So, we come to the conclusions. How much protein is required to cause improvements in weight management?

First of all, we note that there is evidence to suggest that lower amounts of protein (0.8 grams of protein per kilogram of weight per day) during energy restriction may be sufficient for weight and fat loss, while higher amounts of protein (1.2 grams of protein per kilogram of weight per day) are required to maintain lean mass.

However, this review found that the average change in usual protein intake in studies that found higher protein intakes to be more effective was +28.6%.

So, if we assume that the usual protein intake in adults is, on average, 88 g/day (1.07 g protein per kg of weight), then adding only 25-30 g protein/day, up to 113-118 g/day, or 1.38 g protein per kg of weight, would potentially be sufficient to cause long-term improvements in weight management.

Meta-analyses, including short-term energy restriction and long-term weight maintenance studies, suggest that the amount of protein required to improve weight management and cardiometabolic outcomes ranges between 1,2 g and 1,6 g of protein per kg of weight per day (i.e. approximately 89-119 grams of protein/day for women and 104-138 grams of protein/day for men).

Similar conclusions were reached in the Protein Summit 2.0, stressing that at least 25-30 grams of protein should be provided at each meal.

However, if this amount is not sufficient, we can increase the protein.

A complete diet can be considered to consist of 2 things: a minimum intake of protein, carbohydrate and dietary fat and the flexible intake which includes the difference between the caloric values of the recommended daily allowances or minimum intake and the total caloric intake.

If only 10% of the flexible intake is protein, this corresponds to 0.7 grams of protein per kilogram of weight per day, which when added to the recommended daily dose of 0.8 grams per kilogram of weight per day, becomes a total of 1.5 grams of protein per kilogram of weight per day.

If the 20% of flexible intake includes protein, this corresponds to 1.4 extra grams of protein per kg of weight per day, with a total daily protein intake of 2.2 grams of protein per kg of weight, an amount that as we have mentioned above, cannot bring negative effects on already healthy people.

So in practice, 1.5 to 2.2 grams of protein per kilogram of weight per day seems to be a reasonable recommendation for adults as part of a complete diet.

In summary:

  • The first and main reason for a successful diet is the adherence to the diet itself and therefore it is more a matter of psychology and attitudes.
  • Although a high-fibre diet may help in the short term, its benefits are doubtful to translate into the long term, as continuous adherence to such a diet is difficult.
  • 1.2-1.6 grams of protein per kilogram of weight per day, with 25-30 grams of protein per meal seems to be enough to improve weight management and cardiometabolic outcomes.
  • If this is not enough, 1.5-2.2 grams of protein per kilogram of weight per day is a reasonable recommendation.

-Suprastratum: The authority on health, fitness and nutrition

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Author: Nick Krontiris

Founder, Suprastratum

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