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Higher protein intakes naturally lead to less eating later on

Posted Oct 08 2010 11:08am

I usually eat breakfast, but sometimes I drink it. If I’m short on time and it’s too early to eat I might whizz up a ‘smoothie’ with a range of ingredients that cover a number of nutritional bases. Typical ingredients include berries, plain, raw egg, full-fat yoghurt, coconut milk and/or cream, water and a little honey. One of the tricks to eating healthily, I think, is to ensure appetite is kept nicely under control. So, I want this liquid breakfast to sustain me. The protein and fat tend to do the job here (in contrast to a fruit-based smoothie which will not only spike my blood sugar, but give me a whack of fructose, and not sustain me for more than perhaps two or three hours).

One thing I sometimes toss into the mix is some whey protein powder. Part of my rationale here is that it will help ensure that my smoothie will keep my appetite under control until lunchtime. After such a smoothie had at 7.00 or 8.00 in the morning, it’s not uncommon for me to be ready for lunch, but not ravenously hungry, at 1.00 pm, say. This morning is a case in point: I had a smoothie at about 8.15 (a little later than normal), and I’m writing this at 2.00 pm without any great desire to eat.

One of the reasons whey may help here is because, well, it’s protein. And protein, calorie for calorie, tends to sate the appetite more effectively than carbohydrate or fat. Several studies show that higher-protein meals are generally more satisfying, and tend to lead to individuals eating less at a subsequent meal too.

Bearing in mind my some-time liquid-based breakfast, I was interested to read a recent study which assessed the affect of drinks fortified with varying amounts of whey protein on subsequent food intake [1]. The study in question took subjects and have them one of the following 400 ml drinks:

  • Flavoured water
  • A beverage containing 400 calories of which 12.5 per cent came from whey protein
  • A beverage containing 400 calories of which 25 per cent came from whey protein
  • A beverage containing 400 calories of which 50 per cent came from whey protein

90 minutes later, the individuals were given access to an unlimited amount of food, and their intake was measured.

After flavoured water alone, average intake was 988 calories.

Average intakes following the other beverages were as follows:

12.5 per cent whey: 841 calories

25 per cent whey: 808 calories

50 per cent whey: 682 calories

On another occasion, the experiment was repeated but with some adjustment to the preloads.

  • Flavoured water
  • A beverage containing 250 calories of which 10 per cent came from whey protein
  • A beverage containing 250 calories of which 20 per cent came from whey protein
  • A beverage containing 250 calories of which 40 per cent came from whey protein

The results were similar to the first experiment.

After flavoured water alone, average intake was 1147 calories.

Average intakes following the other beverages were as follows:

10 per cent whey: 1000 calories

20 per cent whey: 953 calories

40 per cent whey: 908 calories

What is clear from these two experiments is that when the ‘pre-load’ contains protein, the more protein is had, generally the less is eaten subsequently, even when the pre-loads contain the same number of calories. Here, again, is evidence that protein has potentially useful appetite sating power.

My experience is that eating a decent amount of protein is a key strategy for those seeking to control their appetites. It makes healthy eating easier, usually. We have a vogue here in the UK (as in many other countries) to base breakfast around cereal and milk and/or toast. Not only are these options relatively low-protein, they will also tend to destabilise blood sugar levels in a way that can lead to low-ish blood sugar in the mid-late morning. Many people find that if they eat breakfast they get hungrier than if they eat nothing at all. These people invariably eat starch/sugar based breakfasts. The trick, if you’re going to have breakfast, is to make sure it has a decent amount of protein in it.

Full-fat yoghurt with nuts/seeds and berries is an option, as is eggs perhaps with some ham or smoked salmon. I’ve found relatively protein-rich breakfasts such as these tend to control appetite not just in the morning, but for the rest of the day (including the evening) too.

References:

1. Astbury NA, et al. Dose–response effect of a whey protein preload on within-day energy intake in lean subjects. British Journal of Nutrition. 28 September 2010 [epub before print]

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