A subject that is typically raised by clients, in the initial weeks of our working together, is calories. How many should a person take per day? How many per meal? At breakfast? After training? My response is that calories alone do not dictate fat loss. Before people start choking on their slim-line sandwich and writing streams of vitriol in the comments section - let me explain.
Calories are a unit of energy. Whilst the human body burns calories for fuel, it is a far more intricate and complicated process than a steam engine happily chugging along as coal is continually added to the furnace.
All calories are not created equal. Let's say someone decided to work out their BMR (basal metabolic rate) and decided to cut their calories by 500 per day. So far so good. However, if they chose to eat simple, refined carbohydrates (or even the wrong grains or carbohydrate sources) and continued to drink alcohol as a part of their revised dietary intake, they are not going to lean down. Obesity and fat accumulation are due to poor nutrition, toxicity, inflammation and stress (plus too little exercise, dehydration and insufficient sleep.)
If you are eating clean, fresh and nutrient dense foods with an idea of appropriate portion size you are going to find it very hard to eat massive quantities of food or surplus calories. This can partly be attributed to satiety and also because clean foods are not excessively calorific (the exception in my experience being nuts or peanut butter consumption which can sometimes be hard to control initially.) I'd rather provide a meal plan and recipes than have a client wondering around like a nutritional zombie doing continuous mental arithmetic to ensure that they fall within a prescribed calorie limit. I have clients with hectic professional lives, who have lost over 20kg of fat like this, and I think these plans are especially effective for those with demanding lifestyles.
Hormones also have a huge impact on fat loss. The calories you eat are processed, stored and utilized very differently depending on your hormone balance. Someone who is stressed, tired, dehydrated and eating inappropriate foods for their body type (irrespective of calories) will not have optimal digestion, absorption or body composition. Hormones are chemical messengers that travel around the blood stream to their target cells/tissue and elicit a response. Growth, repair, sleep, digestion, sex drive and energy expenditure are some of the functions that they influence. They do not, however, work in isolation and some will dominate others via hogging cell receptors, diminishing levels of, and sensitivity to, others. They profoundly impact the way we use the calories we eat.
Let's take stress as an example. In an evolutionary sense, humans are designed to deal with acute stress. Being chased by a sabre-tooth tiger is a rare phenomenon these days, but our ancestors faced this problem- and it was normally over pretty quickly. The 'fight or flight' response which was and is designed to mobilise energy in the face of a physical stress, is complicated by our brains not being able to differentiate between a real threat and a hypothetical one. If you are worried about deadlines, commutes, money and any other of life's questions - you are not alone but are also stimulating a stress response. This is compounded by the fact the stressful situations we encounter rarely involve a physical response. Instead we are usually sitting in a delayed tube, in a meeting or behind a desk - despite this we will always mobilise energy in the face of stress.
Stress does not have a calorific value but it has a huge impact on how we use the energy in our cells and liver. Cortisol (a hormone produced by stress) reduces inflammation, releases glucose into the blood stream and initiates a hunger response (to replace the energy you have expended fighting or running away from stress). Modern life is very stressful and this results in repeated adrenal responses. The problem with prolonged cortisol in the blood is that it will disrupt and diminish levels of human growth hormone, testosterone, whilst reducing thyroid output (not good if you want to be lean, strong and have a healthy metabolism). It will also interfere with insulin (the fat storage hormone) and disrupt blood sugar levels, concentration and appetite.
High levels of insulin and cortisol are not good. Partly as they do opposing jobs (telling your cells to store and release energy accordingly), with both having to rise in competition with one another. Excessive insulin will produce an inflammatory response. Your kidneys will retain water and your blood pressure will rise, both of which will leave you feeling bloated. Excessive cortisol is then released to reduce inflammation, but will lead to fat being stored around the belly (so it is within range of the liver) and a further rise in blood sugar. This then leads to a release of insulin, and the downwards cycle continues. If you are eating refined carbohydrates, too much fructose, or ingesting adrenal stimulants like coffee, sugar and caffeine, coupled with being stressed and tired then your body will suffer: with all these blood sugar fluctuations - you've created a hormonal traffic jam.
I would never dream of telling a successful, driven and hard working client that they should chill out and stop worrying about things. It is stupid advice and unrealistic. There are, however, a number of ways in which people can lower their exposure to stress and that includes eating the right foods, training at an appropriate intensity, practicing breathing exercises or yoga and making time for themselves. I'd far rather help them achieve that than encourage them to count calories.