The word ‘metabolism’ comes from the Greek ‘metabolē’ meaning ‘to change’ and includes all the chemical reactions that take place in a cell that are necessary for it to live. When many people think of metabolism, they think of food and drink or a huge diagram of metabolic pathways with thousands of connections. However, understanding metabolism is the key to understanding life and it has undeniably been a subject of fascination for biochemists for more than 150 years.
Metabolism refers to the entire sum of reactions taking place in the body in every cell and providing the body with energy. Energy metabolism at the level of the whole organism and cells and even organelles (i.e. mitochondria) needs to be properly regulated in order to maintain or improve metabolic health. Every living organism uses its environment to survive by taking in nutrients and substances that act as building blocks for movement, growth, development and reproduction. The rate of energy production is called basal metabolism and depends on factors such as gender, age, physical activity, diet, hormonal balance, genetics and health. In women, it additionally depends on the phases of the menstrual cycle. Most factors are beyond our control, but it is thought that certain behaviours, particularly diet and exercise, can affect resting metabolism – but for how long and to what extent – this is not well defined.
What speeds up metabolism?
1. a meal eaten in the morning
The consumption of food stimulates energy expenditure. This is a well-known phenomenon known as the thermic effect of food (DIT). This effect is responsible for ~10%-15% of the total energy metabolism, which represents a significant amount of the daily energy expenditure of the human body.
Currently, there is a great deal of interest in the possibility of modulating this effect to increase the body’s energy expenditure and aid weight loss. First of all, it has been shown that this effect is influenced by the timing of meals, with the effect being higher in the morning and lower in the evening. Increased nocturnal insulin resistance and increased ghrelin levels, slower evening gastric emptying with increased carbohydrate absorption and increased morning sympathetic nervous system activity have been proposed as possible explanations.
2. Adequate macronutrient supply: complete protein, vegetable fats and fibre-rich carbohydrates
Macronutrient composition appears to significantly influence postprandial energy expenditure, even if the data in the literature are controversial. It is widely believed that proteins cause increased energy expenditure, which, combined with a greater satiating effect, may determine greater weight loss. On the other hand, carbohydrates and lipids determine a lower DIT than proteins (protein > carbohydrates > lipids).
Meals with a protein content of 11% to 30% of total calories proportionally increase the DIT up to a value of 30%, where a plateau occurs and further increases in protein intake do not further increase the thermal effect of the food. It is also important to consider the source of the protein: casein, soy or whey proteins are metabolised differently, which may explain the variability in the rate and degree of increase in DIT. In particular, whey proteins lead to higher DIT than casein, while the opposite results were obtained comparing whey and soy proteins. Regarding the quality of other nutrients, medium-chain fatty acids appear to increase DIT more than long-chain triglycerides, and unsaturated fats more than saturated fats. Finally, unrefined, fibre-rich carbohydrates condition increased energy expenditure, especially those contained in low-processed foods.
3. increase muscle mass, physical activity in general and spontaneous physical activity in particular
Studies in mice have shown that an adequate amount of muscle mass can prevent both insulin resistance, type 2 diabetes and the development of obesity through excessive energy supply. Muscle hypertrophy in mice (hypertrophy) prevents lipid accumulation and reduces insulin resistance in muscle. These results suggest that muscle may produce a factor that regulates food intake. This feedback may take place through a direct muscle-brain axis via an unknown myokine acting on tissue that transmits satiety signals to the brain. Surprisingly, increased muscle mass decreases rather than increases food intake.
Consistent with the cross-sectional observation of reduced spontaneous physical activity in obese people, studies have shown that spontaneous physical activity is lower in obese people. Increasing spontaneous physical activity may help to speed up metabolism and increase energy expenditure.
4. EPA and DHA fatty acids
New findings revealing the nutritional power of fatty acids as part of the triglycerides of fish oil or krill oil (and its components), which contains high levels of phospholipids consisting of a glycerol skeleton with two fatty acids (EPA or DHA). Sistilli et al. demonstrated impressive antifatty effects in the liver by krill oil compared to fish oil in animal model studies using obese, insulin-resistant mice. Furthermore, effects were observed in both preventing and reversing hepatic steatosis. This was associated with improved liver insulin sensitivity and high plasma adiponectin levels.
5. Periodic fasting, intermittent fasting
Alternating cycles of fasting and refeeding stimulate specific biochemical reprogramming aimed at utilising stored energy during periods of fasting, known as fasting physiology. It is presumed that the repair mechanisms integral to fasting-refeeding are optimally active during fasting periods. This means that intermittent and intermittent fasting may trigger factors that improve overall health. Fasting can be a tool in reducing body weight, improving dyslipidaemia and blood pressure. Although further research on long-term outcomes is needed. In contrast, this approach should be avoided for certain health conditions. Intermittent fasting should be considered as an option for people who have a pattern of unhealthy weight gain using standard dietary patterns.
6. Hormonal balance and efficient functioning of internal organs
The pancreas is a key metabolic organ that regulates the amount of carbohydrates in the blood, releasing significant amounts of insulin to lower glucose levels or releasing glucagon to raise blood glucose levels. The use of carbohydrates and lipids by the body is called the Randle cycle and is regulated by insulin. The liver, in turn, is the organ responsible for processing absorbed amino acids and lipids from the small intestine. It also regulates the urea cycle and basic metabolic processes such as gluconeogenesis and glycogen deposition.
Thus, there is no doubt that the proper functioning of these organs has a beneficial effect on metabolism.
7. Caring for the gut microbiota
As the study showed, sodium butyrate supplementation increased energy expenditure in mice by inducing mitochondrial function in brown fat and skeletal muscle. Thermogenesis and fatty acid oxidation were also increased. The microbiome regulates energy balance through different mechanisms: control of the gut-brain axis both at the level of nutrient sensing mechanisms in the gut and at central nervous system integration sites. The gut microbiota of obese mice has been shown to have a greater ability to extract energy from the diet, and genes related to phosphotransferase systems involved in microbial carbohydrate processing have been shown to be increased in both obese mice and humans.
8. Substances of plant origin
Overall, there is very little data available on this topic, and the clinical relevance of a single nutrient or a single food is unclear in a weight loss strategy.
Clinical, in vitro and in vivo studies of substances and products such as capsaicin, caffeine, piperine, curcumin, carnitine, ginger, bitter orange, cinnamon, cloves, tea, pineapple, Garcinia cambogia were analysed. Most of these have shown beneficial (albeit small) effects on metabolism, although further clinical studies are needed to prove their efficacy in humans and to establish safe doses.
New substances
Recent studies optimistically indicate a positive effect of nucleotides in accelerating metabolism. Further research is worth watching. Dietary nucleotides influence the body’s processes related to lipid metabolism, enhance resistance to infection, modulate the immune response, and support tissue growth, development and repair. It is no wonder they are in such high demand from many people looking for new ways to improve health or boost immunity.
Summary
In Western societies, the availability of highly processed foods and general lifestyles have contributed to creating an obesity pandemic. In an attempt to address the inevitable weight gain, the search for substances or foods that can increase energy expenditure has begun. However, only a few foods have the potential to affect energy expenditure – but consumed in much larger quantities than those normally consumed. In humans, energy balance is complex and multifactorial, and physiological compensation occurs with changes in energy intake and/or expenditure.
Author: Zuzanna Cybulska, MSc, clinical dietitian
Literature:
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- Aisha Farhana1; Anis Rehman2