24. High protein or high carb diet?

Why do people follow a high-protein diet?

In order to lose weight, many people are following either a high-protein/medium-fat/low-carb diet, or a raw-vegan diet (high-carb/low-protein/low-fat). The high-protein diets (Paleo/Atkins/Harcombe etc) are very popular as they almost guarantee weight loss without having to count calories or restrict portions. How does this work? We need to look at what happens to food when it’s digested.

Very simply:

  • When carbohydrates are eaten and digested, glucose is created, which goes into the bloodstream as an energy source. If there is too much glucose in the bloodstream at any one time, the pancreas injects insulin into the bloodstream. This allows the liver to turn the glucose into glycogen and store it for later use (in the liver and muscles). When blood sugar levels drop, the liver converts the glycogen into glucose and pushes it in to the blood stream. Glucose from carbohydrates can only be stored as glycogen in limited quantities.
  • When protein is eaten it is broken down into bits called amino acids, ready to be reconstructed as the body needs these building blocks. Stored protein can be used as fuel in lean times, when it is broken down into glucose.
  • When fats are eaten they are broken down into fatty acids that travel about in the blood and get used by cells that need the energy. Fatty acids that don’t get used quickly get stored in fat cells (that have unlimited capacity), and when blood sugar is low, the pancreas produces a hormone called lipase which breaks the stored fat into fatty acids and puts them in to the bloodstream, ready to be used for fuel.

In summary: both carbohydrates and fats provide the body with energy, and if there is too much glucose or fatty acids in the bloodstream, these are stored as glycogen and fat for later use.

What this means is that if you sit down and eat a meal of carbohydrates and fat (bread and butter, potato with sour cream, fish and chips) the energy from the carbohydrates will be used first as this is immediately available as glucose, and the energy from the fats will be stored.baked-potato-522482_640


If you eat a high-protein/low-carb-medium-fat diet , you have very little glucose in the bloodstream for energy, so the fats you eat provide the energy you need.

If you keep your fat intake fairly low, at some stage you will have burned up the fatty acids in your bloodstream, so your body breaks down the fats stored in your fat cells, and you lose weight.

But, before you rush off and buy a leg of beef, be warned – there are inherent dangers in this type of diet:

  • You can increase your risk of osteoporosis as high amounts of protein require high amounts of calcium to digest it, and if you don’t eat enough calcium-rich foods, your body will leach the calcium from your bones.
  • Your kidneys are responsible for filtering protein from the blood, so they can take strain if faced with having to filter high quantities of protein as well as the waste products created when protein is processed.
  • When your body turns fat into energy (whether this is fat you have just eaten or fat in your cells), this creates ketones. Some ketones are used by the brain and heart and other organs as energy. This is why it is important to eat some good-quality fat. However, the ketone acetone can be dangerous.  This normally gets expelled in the breath or urine, but too much in the system can cause death.
  • If your carbs and fat intake are low, your body will break down protein in your tissues, as well as fat in your fat cells, for energy.

Which is natural: high protein or high carb?

First, let’s look at this in a general natural sense. I will show you how animals tend to eat either a high-carb/low-protein/low-fat diet , a high-protein/low-carb/medium-fat diet, or a medium-protein/medium-carb/medium-fat diet, and what they eat has everything to do with their lifestyles and how much energy they expend in daily living and in getting food.

Lions, tigers, leopards, cheetahs, wild cats, panthers, wild dogs, foxes, wolves etc will hunt an animal to eat, taking some time ans spending lots of energy over the process and not being successful each time they try. They may go for days without food. When they do catch an animal, they eat huge quantities at one time, and they eat the muscles, fat, skin, hair, blood, intestinal matter (which helps digest the food) and bones (which supplies them with calcium and prevents bone density loss as explained above). Their diet is high-protein/medium-fat/low-carb, and when they eat, which is not often, they gorge on food. They exercise vigorously when hunting, but spend the rest of the time being fairly sedentary. Here is a video of lions with their kill:

Horses, bison, elephants, cattle and  some species of baboon eat mainly grass and leaves and any grains and seeds that come with this. This is a high-carb/low-protein/low-fat diet and these animals keep on the move, eating often, yet taking time to rest and digest food. They don’t run unless they need to, or in play or courtship. This is a video of wild horses grazing:

Monkeys, mice, birds, squirrels and rodents graze all day on fruits, grasses, grains, insects, eggs, nuts and anything else they find edible as suited to their species. They are constantly on the move, and they move quickly, and they eat almost continuously as they find food. This is a video of a Spider monkey eating fruit:

Gorillas and orang-utans eat leaves, fruits, roots and insects. Chimpanzees and baboons eat anything, including small mammals and birds, if they can catch them. They keep fairly active, though spend quality time resting. They tend to eat regularly but not constantly.

So this shows that high-protein and high-carb diets are natural, and that the respective animal types’s energy expenditure balances out the calories they gain from the food they eat.

Match the type of food you eat to your lifestyle and exercise regime

Orang-outang up a tree eating leaves

Orang-outang eating leaves

In nature, if food is easy to get, it probably has a low energy value, so animals need to eat a lot of it and often. Foods with higher energy values take either a lot of time or a lot of energy (or both) to get hold of, so less of it is eaten (they are not eating all day as do fruit eaters) ensuring that in the natural world, animals don’t eat more food than their bodies need.

This is how nature keeps a perfect balance. Think about it: you don’t see obese monkeys, lions or squirrels, yet they don’t diet. Nature makes sure that the amount of effort and time they are prepared to put into finding food is related to the energy value of the food.

Humans have bypassed this formula, though, and many people who rarely do any vigorous exercise have easy access to high calorie value foods, causing weight problems.

Which is the most ethical diet?

Our ethics, as we have seen, involve not killing, especially not killing animals. So, this makes it very difficult to eat an ethical high-protein/low-carb diet, since there is no low-carb plant food available. Thus, we are left with:

  • Raw foods (fruits and greens) (high-carb/low-fat/low-protein) for those who donlt exercise too hard.
  • Grains/legumes/roots/starchy fruits and greens (high-carb/low-fat/low-protein) for those who go tot he gym or play sport.
  • All of the above plus oils, nuts and seeds (high-carb/medium-fat/medium-protein) for those who do sport that burns lots of energy.

And here is some inspiration for those are still considering going vegan (or natural/ethical):

How do you plan your meals as a vegan? Do you struggle with ill-health or weight problems? I would love to hear from you.

Next post: Is food combining natural?





Image credits:

Hairy Orangutan Eating by papaija2008






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