This depends hugely on where you're referring to, though generally, the answer is no.

If you're talking about Africa, for example, living standards and average food intake have been falling consistently throughout the 20th century, and probably hit a high point sometime around the 15th and the 16th centuries, when various strong polities dominated Africa and she was largely free of outside influence. This time period also coincides with the little ice age, which probably made the harsh continent a little more hospitable. So often, living standards can be dramatically impacted in the very long term, ie, hundreds of years by something as simple as the weather.

In Europe, living standards have been steadily rising, but if we're talking about health, it took a huge dip in the 19th century as she catapulted head-first into the industrial revolution. In Britain, life expectancy fell drastically, being as low as the mid 30s in some seriously industrialised areas. She also saw a slight dip in certain places with the Roman Empires exodus. Though the effect of her withdrawal is usually exaggerated, places where she was ejected relatively suddenly, like, again, Britain, saw deterioration of urban areas as they became occupied by peoples who traditionally didn't build cities, and so couldn't look after them, so societal collapse can often lead to a drop in living standards.

Much of China has been in decline for hundreds of years, the average Chinese person probably would have been better off in the high point of the Tang empire, in the 9th century, than they would have been in the late Qing, in the 19th century. In fact, the Chinese refer to the current 'era' as the 'century of humiliation' - though it has been a bit longer than 100 years - because the quality of life for many of her citizens has been declining as a result, in their eyes, of Western meddling in her affairs.

So in general, not really, there are plenty of examples of freak weather, societal collapse, or outside pressures, forcing down living standards for centuries, though again, it varies heavily depending on ones location.