Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: chris on 03/07/2017 18:05:27
-
Recently I decided to overhaul my lifestyle and diet. I had noticed that, since taking on a big computer project - i.e. re-building this website in its entirety - I was spending a lot more time sitting down, yet I was eating the same amount. Consequently I noticed that I had gained a bit of weight; not enough to show and not enough to make me even beyond a normal BMI, but enough to register mentally and make me realise that I was on a slippery slope.
I decided to do something about it. So while I was in Australia for a few weeks in May, I used to opportunity, and the complete change of scenery and environment, to overhaul my lazy lifestyle.
I used the fact that I was awake and raring to go at 5am (aka jetlag) to get up and go walking. I eschewed junk, I ate a lot more protein at breakfast, I significantly reduced my portion sizes and I've substituted fruit for crisps and I have eaten no snacks between meals.
Since returning home, I've maintained my improved lifestyle. I am enormously self-disciplined, so I genuinely have maintained a very low-calorie diet - probably about 1200 calories a day - which sounds horrendous but it's truthfully not been at all difficult.
Gratifyingly, but slightly worryingly, when I stood on the scales the other day I realised I'd actually shed more than 1 stone, and I wasn't that heavy to start with.
Most people would probably be delighted, but the problem is that, despite eating a lot less, I honestly don't feel correspondingly more hungry than when I was probably eating twice what I now do. So I'm now going to have to train myself to eat more again, otherwise I'm going to lose too much weight!
What a problem to have eh?
But my question is, would you agree that the more you eat, the more you get used to eating, and hence the hungrier you tend to feel? I have obviously shifted my metabolism quite effectively to use energy more efficiently that it did before, and to liberate calories from other sources - such as body fat - but without feeling uncomfortably hungry or getting the low-sugar shakes like I used to come tea time. Fascinating. Eat less, feel less hungry...!
Anyone else had a similar experience?
-
I think that if you get a bit hungry before the next meal, then you are eating roughly the right amount.
If you get to the next meal, and you don't feel hungry, then eat a very light meal (or none at all).
It's a bit hard at a holiday resort or on an ocean cruise, where there is an "all you can eat" buffet.
But if you eat lots of non-starchy vegetables, there isn't room for much else.
The goal is to retain a healthy moderate weight.
-
Actually, I think the real demon is sugar. There is so much covert sugar in everything these days. The drive for low fat means that flavour has been replaced by sweetness. And in the same way that we get used to the amount of salt we add to food, or how sweet we like our tea, I think we are sensitive to how much sugar we eat in food. As a result, things don't "taste right" without extra sugar, or we eat more to compensate and titrate intake up to that to which we have become accustomed.
-
This is a somewhat difficult topic for open discussion, as formulated, because of the high rate of eating disorders. Failure to eat sensibly is a risky business and I urge caution in both discussion and experimentation. However, I agree. My personal experience is similar. Typically this 'switch' takes some time to occur - perhaps two weeks or so.
-
This is a somewhat difficult topic for open discussion, as formulated, because of the high rate of eating disorders.
You're right, of course, that we don't want people to develop an anorexic or bulimic problem by encouraging under-nutrition or an injudicious eating habit, but the elephant in the room here, excuse the pun, is surely the 50% of the world population that swing the other way and eat too much. That's a pretty severe eating disorder too, which in the UK costs the NHS upwards of about 10 billion per year owing to the association with diabetes, metabolic syndromes including fatty liver, elevated cancer risk and joint disorders. Yet everyone *****-foots about around obesity and overweight to avoid offending anyone. If you're fat it's because you eat too much. It's shocking that 25% of children starting school in the UK are overweight; that number rises to a third in some cases by school leaving age.
I think we need decent nutrition education in schools, starting with the rule that energy in = energy out; or, as an American friend put it, mouth hole bigger than arsehole = weight gain...
-
I have two working theories on this: the first slightly more established, the second more of a "watch this space". Here goes:
1) Hunger isn't as simple as a measure of the volume of food consumed, but also of the quantity of particular nutrients. I strongly subscribe to the idea that the body seeks to obtain any nutrients that it is deficient in, although sometimes it is misguided on what it must eat to obtain said nutrient. An example of this is when severe nutritional deficiencies can lead to "pica" (the abnormal craving and consumption of non-food items). It appears that when the deficiency of nutrient is severe enough, the body is willing to have a go at eating ANYTHING to try an obtain that nutrient. Similarly, pregnant females are frequently reported to crave very unusual food items during pregnancy; perhaps due to extremely high nutrient requirements for both mother and foetus.
In Western society, there are plenty of easy-access food products that border on the definition of "non-food items" and are quite low in their nutrient content (other than fat, salt and sugar). Therefore, if a large part of your diet comprises of such low nutrient items, you are going to end up deficient in essential nutrients such as proteins and vitamins. In order for your body to then find those nutrients, you are going to have to eat even more food, until the required nutrients are obtained. If you eat highly nutritious foods (eg. vegetables and whole foods), you may be able to correct the nutrient deficit while ingesting a relatively low number of calories. But if you eat nothing but potato chips, it is going to take a really large amount of chips, along with a REALLY large number of calories to fulfil your nutrient requirements.
An animal nutritionist told me that different animals have different core nutrients that drive hunger and satiety. For example, grazing herbivores often need to eat a certain amount of fibre before they feel full and stop eating, while primates need to eat a certain amount of protein before they feel full. For either group, if they don't get enough of that nutrient, they will likely continue eating and be at risk of obesity. This is probably a gross oversimplification. But you mentioned that you were eating more protein at the start of the day, and have possibly replaced a few high-energy, low-nutrient foods, with a variety of low energy, high nutrient foods. Which may be part of the reason that your hunger (or desire for nutrients) is reduced for the rest of the day.
2) The second theory revolves around the resident gut bacteria (the “gut microbiota” or “gut microbiome”), possibly the most underrated organ of the human body, consisting of bacteria, protozoa, and even worms. The importance of the gut microbiome is more obvious in some species than others. Specialist herbivore species (eg. horses, rabbits, guinea pigs, ruminants, koalas, kangaroos) may very well die from severe disruption of the gut microbiome (dysbiosis) through the use of certain oral antibiotics. The role of the microbiome becomes less obvious in omnivores and carnivores, although, I believe is still important. Recently, I personally experienced severe illness and inability to digest any food other than dairy products after a course of antibiotics, which was a dreadful experience.
The types and proportions of organisms that make up an individual’s gut microbiome can be dependent on what species you are, but also by diet (more so in some species that others). For example, the gut bacteria in a baby mammal drinking milk can be vastly different to the bacteria in an adult of the same species, who consumes mainly solid food. By feeding the bacterial population a certain type of food over a long period, certain species of bacteria that thrive on that food are likely to do better that other species that prefer a different type of food substrate. Suddenly changing the diet from Food A to Food B, is potentially going to 1) upset the population of bacteria currently in the gut that has adapted to thriving on Food A, and 2) result in less efficient digestion and uptake of energy since the current bacteria may not be very good at processing Food B. An example of this is that dogs and cats that are suddenly switched from one brand of food to another brand (because the bag of food ran out) frequently develop diarrhoea and gut discomfort, whereas pets that are slowly transitioned over a number of weeks do a lot better. Also, trying to eat red meat after many years of not eating it at all is a really unpleasant experience.
This could potentially explain how many people who diet for weight loss for the first time report experiencing great success initially, regardless of what the new chosen diet actually is (eg. Atkins, paleo, salads, smoothies, potatoes…), but later seem to “plateau” and even gain the weight back after a while, despite sticking to the diet and exercise plan.
A good scientist would collect a faecal sample before, during and after dieting, for analysis. ;)
-
@SquarishTriangle Brilliant post; thank you. Your point about nutrient deficiency is very articulately made. It sounds very plausible, but is there actually some evidence base to support the hypothesis?
I agree, meanwhile, that the link between the microbiome and weight loss and weight gain (https://www.thenakedscientists.com/articles/science-news/bugs-block-keeping-weight) is pretty clear
-
I find it pretty challenging to sort though the literature on nutrition, but here is a fairly comprehensive review on the role of dietary protein in satiety and weight loss:
Westerterp-Plantenga MS, Lemmens SG and Westerterp KR (2012). Dietary protein – its role in satiety, energetics, weight loss and health. British Journal of Nutrition; 108, S105–S112.
https://www-cambridge-org.ezp.lib.unimelb.edu.au/core/services/aop-cambridge-core/content/view/CCA49F7254E34FF25FD08A78A05DECD7/S0007114512002589a.pdf/dietary_protein_its_role_in_satiety_energetics_weight_loss_and_health.pdf
Another interesting paper on pica and cissa:
Touyz LZG, Ferrari CIC (2016) Odd Cravings, Appetite, Hunger, and Thirst. Int J Dent Oral Health; 2(4).
https://www.sciforschenonline.org/journals/dentistry/article-data/IJDOH-2-189/IJDOH-2-189.pdf