Why is it difficult to lose weight?
Protein leverage is an interesting concept which may help to explain why so many of us find it difficult to manage our weight. We have all the motivations and all the goals set on Mondays. Faced with the choice of what we feel we should and shouldn’t eat Monday lunchtime we still find it difficult to choose well.
To understand protein leverage it is important to comment on the current Western Diet. Whether or not you have bought into veganism, or are still just a plain old omnivore it is easy to choose unhealthy foods. Our Western Diet is highly processed, and very high in fats and sugars. What is notable is that the sandwiches and muffins, the take-aways and ready meals that we are all eating, are for the most part protein poor, carbohydrate and fat rich. Even if you choose the skinny range, relatively speaking your meal is likely to be protein poor. Many highly processed meals will have sodium or umami added – flavours traditionally found in protein containing foods – as if to trick us there is more protein to be found in this meal, so we want more of it.
Learning Point: highly processed meals tend to be protein poor.
How much protein do we eat?
This is where protein leverage comes into play. When populations are observed with regard to their usual dietary intake, most populations tend to consume around 15% of their energy intake via protein, with the rest of their energy needs being met by carbohydrates and fat. Some populations will enjoy more carbs and some more fats, but protein intake seems to remain fairly constant in terms of % of energy intake, and also in terms of volume of intake.
Protein leverage suggests that protein is the most satiating and the most tightly controlled macronutrient. Essentially, we stop eating protein when we have achieved our requirements. In experiments where people are allowed to eat freely of carbs, fats and protein containing foods, subjects will tend to maintain protein intake but over-consume on either fat or carbohydrate. The conclusion being that protein intake is tightly controlled by the body, but carbohydrate and fat intake is not. It may be that we have an ancestral drive for fats and sugars, foods which may have been scarce when we were hunters and gatherers. As the Western diet has become more highly processed, our need for protein drives us to keep eating protein poor but energy rich (carbs and fats) foods until we have achieved sufficient protein for our needs.
Learning Point: we regulate protein intake much better than carb or fat intake
How is protein different to carbs and fats?
Looking to the metabolism of protein. We know:
- protein takes longer to break down than fat or carbohydrate;
- spends longer in the gut than the other macronutrients;
- has a higher satiety ranking i.e. we feel fuller sooner and for longer when we eat meals containing about 20% energy from protein;
- and protein uses up more calories being metabolised than fats or carbs.
Learning Point: Meals containing 20% energy from protein help us feel fuller sooner and for longer
We know that the body has an ability to absorb only a certain amount of protein at any one time. Research suggests if we straddle protein across the day it helps with weight loss maintenance. Protein enhances our ability to manage our appetite, in a way that neither carbs nor fats do. It seems an obvious conclusion that if you are trying to lose weight, or maintain a weight loss you have already achieved, having enough good quality protein at each of your meals can only optimise your chances of realising your weight management goals.
Learning Point: Get to know all good protein sources and ensure you have enough at each meal to optimise your nutrient intake and manage your weight better.