Does eating too many carbs cause sugar spikes, insulin resistance? Why you need good cholesterol food, millets to lower them?

To understand why the consumption of excess carbohydrates leads to insulin resistance – and diabetes – we need to understand why it happens. Excess carbohydrates can lead to obesity, particularly central obesity or fat in the abdominal area. While this fat itself can lead to the insulin not working properly, a person with central obesity is likely to have fat deposited on their liver and their muscle. Without all the fat, the insulin can work smoothly and easily burn off the glucose. The fat acts like an obstruction that slows down the activity of the insulin.

Coming back, rice and wheat when consumed in moderation do not lead to insulin resistance. But we do not consume it in moderation – it is the main part of our breakfast, lunch, and dinner. Rice or chapati is the main component of our meals and everything else is an accompaniment. Instead, there is a need to create a plate where vegetables make half of it, proteins a quarter, and carbohydrates just one quarter.

To improve the plate, the highly polished rice and refined wheat can be replaced with complex carbohydrates such as whole grains, millet, and oats.

Now, let’s come to foods other than these carbohydrates. Most of the fruits are okay in moderation. However, certain fruits like bananas, mango, and other highly sweet fruits, can also lead to insulin resistance. This happens particularly with fruit juices where there is no fibre left.

Next, we need to take a look at the fats that are used in our food. It is the saturated fats – such as high-fat dairy, ghee, vanaspati, coconut oil, and palm oil – that lead to insulin resistance. Broadly, remember any oil that remains solid at room temperature – including trans fats that are the greasy, solid layer seen on many desserts – can lead to insulin resistance.

The unsaturated fats – mainly mono-unsaturated fats like olive oil, corn oil, groundnut oil, sesame oil (gingelly oil), and mustard oil – don’t produce insulin resistance. While mono-unsaturated fats are the best, poly-unsaturated fats such as sunflower oil and safflower oil are also quite good.

The other thing that can give you fat is meat – red meat has definitely been shown to produce insulin resistance. But lean meat like poultry or fish is good; in fact, fish contains omega-3 fatty acids that can actually reduce insulin resistance. Vegetarians can include Bengal gram, green gram, rajma, and mushrooms in their diet as they are low in carbohydrates, high in fibres, and high in protein. Soya is also very good, with a very high 40% protein content.

Then we come to vegetables – there has to be lots of fresh, green, leafy vegetables. Starchy vegetables such as potatoes, yams, beetroot, and tapioca should be avoided because they are almost the same as consuming rice and wheat. A broad rule can be to avoid vegetables that grow under the roots, they are usually the starchy ones, except for carrots – carrots are very fibrous and contain nutrients like carotenoids and vitamin A. And also try and eat vegetables like tomato and cucumber raw.

Next, we come to sugars – the World Health Organization recommends that less than 5% of total daily calories come from sugars. So, only one or two spoons of sugar should be consumed during the entire day. In fact, sweetened beverages are the commonest reason for insulin resistance in the West.

Coming to the surprising findings.

We used to think nuts are bad, but for every nut that we have worked with so far – groundnut, pistachio, cashew, and almond – the finding has been consistent. It reduces insulin resistance and decreases weight. They contain a lot of calories, but they are also very satiating. You cannot eat too much – you end up eating less of say rice and roti. If you have say a fistful of nuts at 11 o’clock before your lunch at 1, you are likely to eat less at lunch.

They give you fat, but the right type of fat – the mono-unsaturated fat mentioned earlier.

But while eating nuts, two things have to be kept in mind.

First, the quantity – you cannot polish off a huge amount. Have only a fistful of nuts a day. In fact, Indians have low good cholesterol or HDL levels and the nuts can increase it. For the first time in the world, we showed that cashews can not only increase the HDL level, they can also bring down the blood pressure. Then a study from the US confirmed these findings.

Second, the nuts have to be unsalted.

The other thing that we found in our studies from Chennai is that dairy seems to be actually protective against insulin resistance, obesity, and diabetes. Initially, we doubted it, we thought there may be some confounders. Then we did a 15-year follow-up prospective study of people who did not have diabetes at the beginning of the study and divided it into whether they consumed dairy or not and found that dairy was actually protective, thereby confirming our previous finding.

Among the dairy, yogurt came out to be the best, milk was good, cheese was okay, but butter was neutral. So, you need not give up dairy. Not only is it protective, but it also gives you a lot of protein and calcium. But, again no one should go overboard – don’t drink two or three glasses of milk a day. One glass of milk gives 500 mg of calcium, which is half the daily requirement even for a pregnant woman and okay for a man.

In addition, yogurt also improved the gut microbiota. The foods that we consume affect the gut microbiome. When you have high-fat, salt, and sugar food, it destroys the good bacteria and replaces them with the bad ones. This leads to leakiness of the gut which causes inflammation, which again leads to insulin resistance.

Other than diet, the key to reducing insulin resistance is three types of exercise FAR — flexibility, aerobics, and resistance.