under eating
It’s common for me as a PT to hear many opinions on which diet is the best. How many calories we should be eating and whether we should all be following a low fat, low carbohydrate or high protein diet. Should we be fasting? Eating little and often or sticking to three meals per day? Although I am not a fan of extreme diets, all of these approaches may have a place for certain body types, goals, and activity levels. However, one thing that nobody should be doing is under eating!
I bet you know someone who either after Christmas or before their annual summer holiday decides the best way to get back in shape is to seriously restrict their calorie intake and that doing this will lead to all their excess weight dropping off!! The thing with this approach is that their massive calorie deficit diet is validated, as they will lose weight. However, ‘weight’ is the operative word, not fat!
What happens when you restrict calories?
Our muscles and liver contain stored carbohydrate (glycogen). This is a multi-branched polysaccharide of glucose. For each glucose molecule there are two to three molecules of water attached. This means that whenever you cut calories or carbohydrates these stores will be depleted, so what you’re actually losing is stored carbohydrate and water. It’s also worth noting that an enzyme called glycogen 6 phosphate is needed for the utilisation of glycogen and this is not found in skeletal muscle; this glycogen is used when we are being active, rather than at rest. It is the liver glycogen stores that keep our bloody glucose in balance when it drops below a certain point.
Note - certain body types (endomorphs) have a larger glycogen storage capacity than their ectomorph counterparts who have a smaller storage capacity.
Once the stored glycogen has run out and you are also not eating, will the body turn to breaking down fat for energy? Well, yes. But fat is the body’s most important and long lasting fuel source, so a long term calorie deficit will actually panic the body into holding onto fat and breaking down protein instead. It’s important to remember that protein is biologically active; the more we have, the more fat we will burn to fuel those muscles while at rest.
It’s also worth noting that the body has three types of muscle: cardiac, smooth and skeletal. Not all muscle loss is exclusively from skeletal muscle, but also the other types.
Cardiac muscle is found around the heart
Smooth muscle is found in the walls of the stomach, intestines, bladder, uterus, arteries, veins and capillaries
Skeletal muscle is attached to the bones of your skeleton by tendons
What are the impacts of under eating on the body?
Under eating can make us susceptible to nutrient deficiencies. It stands to reason if we are restricting calories we will not only be restricting macronutrients but micronutrients too. This can have a knock on affect on every system in the body, not least the immune, liver and digestive systems, and can easily cascade into more serious health problems.
The next point is that ‘extreme’ calorie deficits put a stress on the body. When we are stressed we produce a catabolic hormone called cortisol. Cortisol is essentially released to break down fuel for energy when we are in a stressed situation (when the fight or flight process is triggered). There are many things that happen in this state (although they are outside of the scope for today).
While short-term stress equals an increase in cortisol, which causes weight loss (we have all seen a person going through something hard in their life and a side-effect seems to be inadvertent weight loss) it’s important to be aware that long-term stress, with a chronic increased cortisol level, causes the body to panic, as we will be breaking down all those important energy stores. A lot of this breakdown is protein, as the body will hold onto fat as much as it can. So three things happen now that will instead create fat gain:
1. The biologically active protein breakdown will cause the metabolism to slow.
2. Chronic high cortisol panics the body into up regulating fat receptors around fat cells (especially around the belly).
3. Cortisol blocks thyroxine being converted to the more active thyroxine, further slowing metabolism.
Another side note is that stress reduces digestive function, as its more important for energy to be pushed to muscles to cope with the fight or flight situation. This means we may also not be digesting, absorbing and assimilating those essential macro and micro nutrients we need for basic function and health.
Under eating can also affect sleep quality. If our blood sugar drops in the night adrenalin is released to help bring blood sugar back to proper levels and the adrenalin will wake us up. Poor sleep will have a massive knock on affect on liver detoxification, immunity, exercise and work productivity.
It’s important when you go to the gym to work at the right intensity for your body type and goals. Doing this requires our body to be fuelled optimally. If we are under-fed this will affect our training and consequently our results. There are also a host of health issues caused by under eating such as fatigue, malnutrition, osteoporosis, anemia, polycystic ovaries, depression, amenorrhoea and other hormone related conditions. Remember that we need protein and cholesterol to make hormones and enzymes, so this will also affect fertility.
I have met many body building competitors who restrict their calories to get as lean as possible. However, this is done gradually and once they compete they cycle out and increase their calorie intake again. In my experience, most would say that it’s certainly not healthy, but is a means to an end in that particular world. While it’s common practice, there are also many incidences of people becoming ill when they do this incorrectly.
Where does it stop?
If we keep cutting calories, there comes a point that we can’t cut anymore and where do you go from there? Overall, it’s very important to cycle your diet and training so that you don’t plateau. And it’s also essential you eat the correct amount of calories, carb, fat and protein for your specific body type, goal, activity level, height, weight and age.
We’ve developed a calculator that you can use to obtain your optimum calorie and macro levels, which you can access here.
At YBP we are all about up-regulation; help your body to be as healthy, nourished and optimal as possible, while keeping your metabolism firing. In my experience a lot of people are under eating and I have often seen those with an ‘extreme’ calorie deficit actually helped to lose fat by increasing their calorie intake. While this does happen, it’s also true that a lot of people these days do need to be following a ‘slight’ calorie deficit. Whichever scenario is true for you, it’s a really good idea to know what you are eating and how much you need so that food isn’t hindering the results that you’re working so hard for in the gym.
