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With societal development, the temptations of food and life are becoming increasingly abundant. We are surrounded by delicious food every day, and the general pressure of life leads many to relieve stress through food. However, as the days go by, various health problems arise. Therefore, modern people have begun to embrace the "snack" model to avoid consuming excessive calories. But many who follow this approach encounter the same problem: they've eaten less, yet instead of losing weight, they've gained weight. So how can this be solved?
What are the sources of energy for the body?
First, we need to understand the body's energy conversion mechanism. The body's energy sources are divided into three categories: carbohydrates, fats, and proteins.
1. Carbohydrates
Main sources: rice, bread, noodles, sweet potatoes, fruits, etc.
After carbohydrates are digested, they are converted into glucose, which enters the bloodstream to provide energy. Excess glucose is stored in the liver and muscles, forming glycogen and muscle glycogen, which are quickly broken down and used when energy is needed. If carbohydrate intake is sufficient, the body will prioritize burning carbohydrates because they are the fastest source of energy. Burning carbohydrates mainly relies on high-intensity exercise such as weight training, HIIT, and sprinting. Only when carbohydrates are depleted will the body begin to burn fat. However, if glycogen stores are full, excess carbohydrates will be converted into fat and stored in fat cells, causing fat accumulation and, in the long run, obesity.
2. Fat
Main sources: fish oil, nuts, olive oil, avocado.
When the body's blood sugar and liver glycogen are depleted, fat begins to be broken down into fatty acids and ketone bodies to provide energy. Fat is the primary energy source for low-intensity activities, such as walking, light jogging, yoga, and everyday activities, during which a significant amount of fat is burned. Furthermore, during prolonged fasting or low-carb diets (ketogenic diets), the body relies more heavily on fat. Additionally, during long-duration exercises like marathons, glycogen is used initially before switching to fat for energy.
The prerequisites for fat burning:
- The rate of fat burning only increases when aerobic exercise lasts for more than 30 minutes.
- The body will only use stored fat when calorie intake is less than calorie expenditure (calorie deficit).
- During fasting (such as intermittent fasting), the body begins to rely on fat as an energy source, but excessive lack of carbohydrates may also affect athletic performance and muscle loss.
3. Protein
Main sources: chicken, beef, fish, beans, eggs, dairy products, etc.
Under normal circumstances, the body does not preferentially burn protein, but if:
- Glycogen stores are depleted (due to prolonged fasting or extreme low-carb diets).
- Fat burning is insufficient to provide energy (e.g., due to excessive dieting or muscle loss).
- The exercise intensity is extremely high and there is not enough carbohydrate or fat.
The body will then begin breaking down muscle protein, converting it into glucose for energy. This is why excessive dieting or exercise without sufficient nutrition leads to muscle loss, not just fat reduction. So how can we prevent muscle loss?
- Make sure you get enough protein.
- Consume carbohydrates appropriately before and after exercise to avoid using muscles as an energy source.
- Weight training can protect muscles and prevent excessive loss due to calorie deficit.
Is it okay to completely eliminate carbohydrates? What happens if you eat too few?
The root cause of obesity is excessive fat accumulation, and the main reason for this excessive accumulation is the conversion of excess carbohydrates into fat. Therefore, to achieve fat loss, it is necessary to maintain a calorie deficit (calorie intake < calorie expenditure). Thus, many people, even if they eat less...If your daily calorie intake is not less than your calorie expenditure, you will not be able to lose weight and may even gain weight.So, does this mean we should avoid carbohydrates altogether? What problems might arise if we consume too few carbohydrates today?
1. Total calorie intake has not decreased.
Skipping carbohydrates at breakfast may leave your body feeling energy-deprived, leading to overeating at lunch or dinner.
2. Basal metabolic rate decrease
Eating too little or having an unbalanced diet can put your body into an energy-saving mode, reducing energy expenditure. When your basal metabolic rate decreases, you may become more likely to store fat even if you don't increase your calorie intake.
3. Lack of sufficient carbohydrates
Without adequate carbohydrates (such as brown rice and oats), a low-carbohydrate diet can lead to hypoglycemia, making the body more susceptible to stress, affecting cortisol secretion, and making it easier to store fat. Furthermore, a long-term low-carbohydrate diet may also negatively impact athletic performance and reduce calorie expenditure.
In summary, carbohydrates are not off-limits, but only in sufficient quantities to support your physical activity or normal work performance. So how do we determine an appropriate calorie deficit?
How do we achieve a calorie deficit? What constitutes an appropriate deficit?
1. Calculate your daily calorie expenditure and intake (TDEE).
TDEE refers to the total calories the body burns in a day. The formula is "TDEE = BMR × Activity Coefficient", where BMR represents the basal metabolic rate.
BMR can be approximated using online calculators. https://tools.heho.com.tw/bmr/
Activity coefficient selection:
- Sedentary lifestyle (almost no movement): ×1.2
- Light activity (exercise 1-3 days per week): ×1.375
- Moderate activity (3-5 days of exercise per week): ×1.55
- High activity level (6-7 days of exercise per week): ×1.725
- Extreme activity (laborious work or two high-intensity workouts per day): ×1.9
Once you have the above figures, you need to record your daily calorie intake and keep it below your TDEE.
2. Track changes in weight and body fat.
Weight changes alone can be affected by water retention, so it's necessary to combine them with body fat data for a more accurate assessment.
- Weigh yourself 2-3 times a week, preferably in the morning on an empty stomach.
- Use a body fat meter or skin fat clip to observe changes in body fat percentage.
- If you measure your waist circumference and it shrinks but your weight doesn't change much, it means you're maintaining muscle mass while losing fat.
3. Observe physical condition and athletic performance.
A large calorie deficit can lead to fatigue, decreased concentration, and training weakness. Furthermore, continuously reducing weight during weight training may indicate muscle loss. If any of these issues arise, calorie intake should be adjusted accordingly.
4. Hunger
Moderate hunger is normal, but excessive hunger may indicate a large calorie deficit.
Recommended weight changes
If you lose 0.5-1 kg per week, it means that your calorie deficit is adequate and within acceptable limits.
If there is no change in weight after 2 weeks, you can reduce your daily calorie intake by 100-200 kcal or increase your exercise.
However, if weight loss is too rapid (>1.5 kg/week), intake should be increased appropriately to avoid a decrease in metabolism.
