Food Extremist recovery- getting HEALTHY: the realities of the weight loss (if obese or overweight) and weight gain (if anorexic or underweight) journey

The realities of the weight loss (if obese or overweight) and weight gain (if anorexic or underweight) journey

We all know someone who has attempted to lose weight or gain weight. Changes to diet, both for someone over or underweight, can have huge mental and physical benefits in the long term, especially if at weight extremes such as obesity and anorexic BMIs. We talk about the results and how to do it, but never the journey. How do weight loss and gain diets affect your mental and physical health?


The aim of a weight loss diet is to create an energy deficit which leads to dietary fat (and carbohydrates stored in fat), protein and even muscle being used by the body for energy. This causes weight loss. There is not enough energy from the diet so we have to use the energy we have stored on and in our bodies and so as a result, we lose weight. 

When you are trying to lose weight from being overweight or are in recovery from obesity, you may experience the following side effects…

  1. Mental: Lack of focus. Our brains need energy- 60% of the brain is fat and our brain is the most metabolic organ. Despite being only 2% of the body mass, it uses over 20% of energy intake. Multitasking, deep focus, lots of social interaction, lots of mental stimulation and stress and pressure, increase brain output, increasing our brain calorific demand. Lack of dietary calories decreases Dopamine, our reward neurotransmitter, and Serotonin, or pleasure hormone, so we feel less motivated, and happy and are less resilient to stress. Lack of carbohydrates and sugar causes sugar lows which can cause hungry-anger or “hanger” which can make people “tired and wired” where they are angry and irritable and their brains are like cavemen searching for food, and cannot focus or concentrate. It can also cause “hyperfocus” (especially if intermittent fasting) where you can focus extremely well (and are mentally sharp and efficient) on one thing for a short period. Long-term hyperfocus can cause mental burnout. 
  2. Thermogenesis: We use a lot of our dietary calories for warming up our bodies and so weight loss diets and being low weight can make you cold all the time and unable to warm yourself up. 
  3. Sleep: we need sufficient carbohydrate intake to sleep. A lack of carbohydrates can make it harder to fall, and stay asleep. 
  4. Hormonal: what we eat impacts our hormones. estrogen and other sterol hormones and neurohormones such as Serotonin (the brain mood stabiliser) are made of Cholesterol. Insufficient saturated, unsaturated and monounsaturated fat, low cholesterol diets and low body fat (such as in athletes with low body fat: muscle mass ratio or in anorexia or cancer), can cause mood disturbances such as anxiety and depression. This can impact our sense of well-being, our sex drive, and our gastric motility (Serotonin helps control peristalsis and less serotonin causes less peristalsis), reducing appetite. 
  5. Gastrointestinal: food is needed to push food through the colon. Insufficient food can cause slowed digestion, causing constipation, nutrient mineral deficiencies and diarrhoea. 
  6. Skin: insufficient dietary and body fat can cause dry, flakey skin. Insufficient dietary intake of vitamins A and E and K can also impact wound healing. These are fat-soluble vitamins and need fat to be absorbed and so insufficient intake of fat can cause less absorption of these from the diet. 


The aim of a weight gain diet is to cause an energy surplus, where your dietary intake of energy supersedes that of dietary requirement, and as a result, you store excess energy as fat (or glycogen in fat stores or the liver) or muscle. This causes weight gain. When you are on a weight gain diet, such as in recovery from anorexia or trying to gain weight when underweight, you may experience the following….

  1. Mental: lots of excess calories cause sugar highs and lows which can cause mood disturbances such as anxiety and depression. Excess dietary sugar and fat can also cause extreme Dopamine highs which make you manic, irritable and frustrated and unable to focus and concentrate (similar to the symptoms of ADHD). 
  2. Thermogenesis: we use food from our diet to heat us up, so surplus calories can make you hot and sweaty and flushed. 
  3. Sleep: High intakes of sugar and fat can cause sugar highs and lows which can impact REM sleep and make it easy to fall, but harder to stay, asleep.
  4. Hormonal: we use fats to make hormones such as Oestrogen and Testosterone and Serotonin brain neurohormone, and so excess in these hormones can cause hormone imbalances. Serotonin is the mood stabiliser, and Oestrogen fluctuations impact mood, and so changes in dietary fat can cause mood disturbances such as anxiety and depression. They can also increase your sex drive if anorexic or underweight, making you frustrated and irritable (horny) in recovery. This is the opposite to if at a normal body weight, as here weight surplus Oestrogen can cause low libido in men and women, and impotence in men. Diet is personal. Serotonin also increases happiness (so you feel manic if excess) and impacts peristalsis, so impacts your appetite (you feel less hungry). 
  5. Gastrointestinal: excess calories increase the amount of food in the digestive system, resulting in bloating, constipation and wind. Excess wind is usually a sign of overeating. 
  6. Skin: excess sugar and fat can cause skin break-outs and acne as there is surplus dietary cholesterol, causing oily skin. 

Both nutritional journeys come with side effects and impact how you feel, look and your behaviour. They can disempower people towards making the necessary behaviour steps towards health, as they feel too unwell on the recovery journey. It can lock people in food and body extremes (at too high and low weight) of anorexia and obesity. It takes much mental strength and outside support to help people overcome challenges to weight loss and gain and get healthy. 

Copyright Laura Campbell 06/01/2023

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